More than 30 years later and we'll still have what she's having.

When Harry Met Sally, one of the most beloved romantic comedies of all-time, debuted nearly 34 years ago in July 1989, asking audiences the age-old question: Can men and women ever just be friends? 

The iconic film, directed by Rob Reiner and written by the late Nora Ephron, marked Billy Crystal's surprising transition from comedy circuit standout into a Hollywood leading man. Plus, it marked the start of Meg Ryan's reign as America's Sweetheart and one of the ultimate rom-com leading ladies. But neither star was the first (or even second) choice for their now career-making roles. 

A surprise hit that no one saw coming—it was made for just $16 million and went on to earn over $90 million at the box office—so many scenes and lines from When Harry Met Sally have withstood the test of time, becoming some of the most memorable moments in the history of film.

"Baby fish mouth!" ended up sweeping the nation, and "on the side" became a universal punchline. And, of course, who can forget Ryan's infamous Katz's Deli scene in which she shocked America by showing just how easy it is for women fake an orgasm. The movie went on to redefine the romantic comedy, challenging the usual formula and completely turning the genre on its head.

So which other stars were up for the roles of Harry and Sally? And who actually met their future spouse while filming the classic movie? And how did that fake orgasm scene really come to be?

And now, here are 30 secrets you might not know about When Harry Met Sally, as revealed by the stars and in Erin Carlson's I'll Have What She's Having: How Nora Ephron's Three Iconic Films Saved The Romantic Comedy...

1. The inspiration for the movie came when Reiner, fresh off of his success from the classic mockumentary This Is Spinal Tap, set up with a meeting with Ephron, fresh off of Silkwood's success, to pitch her a courtroom drama. She didn't love it. So their meal turned to their personal lives. A few weeks later, they met up again, with Reiner eventually saying: "Two people become friends at the end of the first major relationship in each of their lives and they made a decision not to have sex because it will ruin the friendship. And then they have sex and it ruins the friendship." Ephron was in immediately, and began taking notes as Reiner, who had been divorced for 10 years, and producer Andy Scheinman talked about their dating lives as bachelors, with many of their experiences and quotes ending up in the script.

2. Initially they called the movie Scenes From a Friendship, a rift on Ingmar Bergman's Scenes From a Marriage (1973), one of Reiner's inspirations for the movie. Other titles considered were Boy Meets Girl, It Had to Be You, and Harry, This Is Sally before When Harry Met Sally... was ultimately chosen. It was Reiner's decision to add the ellipses, much to Ephron's chagrin (which was shared by most publications and journalists as they are rarely used in the film's media coverage). 

3. While Ephron initially saw Reiner, best known for his acting work on the iconic sitcom All in the Family, possibly playing Harry, especially given that he was the inspiration for the character, the director wanted a bankable leading man. They approached Michael Keaton, Tom Hanks—"I don't think Tom ever regretted not doing it," Ephron would later say, "because he just never knew how to play it"—Albert Brooks, Richard Dreyfuss…they all passed. All the while, Crystal, a well-known comedic star but not exactly the first actor you thought of when considering a rom-com leading man, was just waiting for the call.

"I knew from agents and managers that [Rob] had met with almost every male actor my age, except me," the star wrote in his memoir, admitting he was nervous to push it because they were best friends. Ditto for Reiner, who said he was "nervous" about the idea, which is why he had to make sure The Princess Bride star really was the "perfect guy" before finally making the call to Crystal, then 40 years old, and the rest is history.

4. The real-life inspiration fro Harry ended up finding love during the movie: While filming, Reiner met his future wife Michele Singer, who came to set to meet her friend for lunch, which Reiner wormed his way into after seeing her. Seven months later, they were married and are still together.

5. As for Sally, Reiner's then-girlfriend Elizabeth McGovern was initially set to play her…but when the couple split, the search was on for a new leading lady. Molly Ringwald was considered, but felt too young. A somewhat unknown Meg Ryan was on the short list with Helen Hunt and Meg Tilly after Susan Dey declined. Ditto Debra Winger and Elizabeth Perkins.

But once Ryan, then 26, tested with Crystal, proving more than capable of holding her own when it came to improvising, Reiner said, "She's perfect."

6. To play Sally, Ryan would end up dropping out of Steel Magnolias, with her role as Shelby going to another up-and-coming actress trying to make her mark: Julia Roberts. (Another sliding doors moment for the two rom-com queens came when Ryan passed on playing the lead role in Pretty Woman, with the film ending up becoming Roberts' star-making vehicle.)

7. "Well, we have to have glasses for the character because...Meg's a lot more attractive than Billy is," was Ephron's alleged reasoning for Sally's specs, with Ryan trying on over 200 pairs before one-of-a-kind La Roche pair (that cost around $5k) caught the star's eye. "These actually do look cute on me," Ryan said, according to Cheryl Schuman of Starry Eyes Optical Services in I'll Have What She's Having, adding the actress kept trying to walk off with them, not realizing they were her prescription glasses. 

"I laughed this nervous laugh. I said, 'What am I thinking, Meg? I would be honored if you took my glasses.'" 20 clones were later ordered in a similar La Roche horn-rimmed style.

8. While Harry was undeniably inspired by Reiner, so many of Sally's quirks in the film came directly from Ephron, including her very specific ordering style. "One day, we were eating lunch, and she's ordering, 'This is on the side, this that,' and I said, 'This has to be in a movie!'" Reiner recalled to The A.V. Club. "I mean, it was crazy the way you're ordering this food. So we put that in as a character trait for Sally."

Like Sally would say, she just wanted it the way she wanted it.

9. For Sally's BFF Marie, Star Wars' Carrie Fisher was cast even though she was best friends with Reiner's ex-wife Penny Marshall; the iconic star, who tragically died in 2016 at the age of 60, would end up stealing almost every scene she was in, along with Bruno Kirby as Harry's best friend Jess who falls for Marie. Kirby, who passed away in 2006, was on Reiner and Crystal's softball team. 

10. "Baby fish mouth!" One of the film's most iconic lines, said by Jess during a game night scene, would end up going on to sweep the nation, and was completely improvised after Ryan just drew her interpretation of "baby talk."

"I [told Meg], 'Do whatever you want to do,'" Reiner recalled to EW. "There was nothing in the script; we just asked her, 'How would you convey 'baby talk'?' It's so perfectly unclear!"

11. Another improvised moment that has gone down in history is Harry's speech to Sally at the end of the movie, declaring his love for her on New Year's Eve in the most realistically romantic way, which all came from Crystal, Reiner revealed: "Stuff like 'I love the way your nose crinkles'—that was Billy—[and] the great line, 'When you realize you want to spend the rest of your life with somebody, you want the rest of your life to start as soon as possible.'"

12. In a somewhat awkward casting decision, Reiner tapped his then 24-year-old daughter Tracy Reiner to play Harry's younger girlfriend Emily (aka Aunt Emily, the famous cake-maker), kissing scene included.

"The scene was slightly awkward for me...because I knew her since she was a little girl and now I have to date her in the movie," Crystal said, with Tracy later explaining the actor, who had been married for 18 years, felt "weird" about kissing Ryan, so she was like a buffer to help him get comfortable. "It wasn't even like a kiss, you know, thank God," she said in I'll Have What She's Having of their quick onscreen peck. 

13. While filming, Ryan had just started dating Dennis Quaid, her D.O.A. co-star. "They were going out," one crew member spilled to Carlson in her book. "She said, 'I know this guy Dennis. He's really crazy about me. But I don't know what to do. Should I get married? Or, what should I do?'"

She would go on to marry Quaid in 1991, with the superstar couple having one child together before divorcing in 2001. The actor later admitted he struggled with Ryan's rise to fame during their relationship.

"When we met I was the big deal," the Frequency star said on Today in 2018. "We'd go out on the streets of New York and it would be like, ‘Meg! Meg!' And I have to admit it, I actually did feel like I disappeared. I didn't think I was that small, but I was. It was a growth opportunity — I learned from that."

14. That four-way phone call that takes place between Harry and Jess and Sally and Marie after Harry and Sally finally sleep together took over 60 takes to get right as one mistake could ruin the whole strategically choreographed scene.

"We shot it 61 times! If you remember at the end, they each hang up their phone—boom, boom, boom boom—in rhythm. It took forever to get it right," Reiner told EW. "We did one I think 54 in, and we did it: They hung up the phones perfectly. Then Bruno blew his last line. So we had to start over again!"

15. Sally's-boyfriend Joe, the one who took her to the airport, was played by Steven Ford, the son of President Gerald Ford. 

16. In one of the first scenes of the movie, Harry immediately turns Sally off when he spits grape seeds out of car window (before realizing he had to roll it down, of course) during their road trip/bickering session. That detail wasn't in the initial script, with Reiner and Crystal coming up with it on set. 

"I wanted to make him a little bit rougher around the edges to start," Reiner explained to EW. "That's what gave Harry his abruptness." 

17. In a full-circle moment, Shakespeare & Company, the independent NYC book store in which Harry and Sally reconnected in the self-help section would end up becoming one of the inspirations for the small book store Ryan's character in Ephron's You've Got Mail almost a decade later.

18. Ryan would later admit to sometimes feeling isolated on set, like the girl on a boys' set, mostly because of Reiner and Crystal's close friendship and standing in the comedy world. "They were very conscientious about making sure I felt OK, because it was very much like a pre-fab relationship that I'd come into," she told The L.A. Times. "Usually, everyone comes in and negotiates their respective positions on a movie. That didn't happen on this one." 

While a crew member described the early days of filming as "very, very awkward," they said in I'll Have What She's Having that Ryan, who formed enduring friendships with Ephron and Fisher, was "pretty at home with things" by the end of production.

19. The idea for the infamous orgasm scene, where Sally proves to a disbelieving Harry that women can fake sexual pleasure, came from an unlikely source: Ryan. Initially, the scene was just supposed to be a conversation, but during a read-through, Ryan said, "Well, why don't I just do it?" Crystal then suggested it should happen at an unlikely place, a restaurant, with the iconic Katz's Deli became the setting, though Reiner initially wanted Carnegie Deli. 

Though it was her suggestion, when the day came to film the scene, Ryan was nervous and was "half-heartedly" doing it at first, before Reiner, directing her to "go full out" took her place to show her exactly what he wanted (and put her at ease), receiving applause from all of the extras. The "very focused" Ryan then did take after take, and "during each break she's run to her trailer," I'll Have What She's Having notes.

The scene would ultimately earn the film its R rating and Ryan her place as one of the queens of romantic comedies. 

20. Later asked why she suggested the fake orgasm for the "high maintenance" Sally, Ryan explained, "The comedy of Sally is so behavioral. It's not so much talking, it's doing, so it was very logical. It wasn't hard to do. We all sat in Rob's office for hours and hours just talking about [the movie]."

21. As for the woman who wanted to have what Sally was having? It was Estelle Reiner, Reiner's 70-year-old mother. He called her to ask if she would come in for one line that could very well end up on the cutting room floor. "I don't care as long as I get to spend the day with my son," she said, according to I'll Have What She's Having. "I'll come, I'll have a hot dog." She nailed it in two takes, with "I'll have what she's having" becoming one of the most famous lines in movie history. 

22. Since When Harry Met Sally's release, Katz's Deli, located on the Lower East Side, has become a major tourist attraction, with with a sign hanging over the booth. And Katz's Deli is more than proud of their role in movie history, even hosting a fake orgasm contest in honor of the film's 30th anniversary, asking fans to recreate the scene on social media. The prize? The "I'll Have What She's Having" package, which is worth $135 and includes a t-shirt, tote bag, pins and all the ingredients to make the sandwich both Sally and Harry were having during the scene. 

23. Ryan has never been back to Katz's Deli since filming the scene. 

24. The interstitials of couples telling their respective love stories that play throughout the film? All real stories, just told by actors, the idea coming after Reiner asked one of his dad's friends how he met his wife. Harry and Sally's one at the end of the film was completely improvised by Crystal and Ryan. 

25. Initially, the movie was going to end with Harry and Sally not ending up together. By the second draft, though, Ephron and Reiner realized they needed a happy ending to sell the movie, though they still believed the "true" finale was the duo splitting up.

"I think for the story it doesn't feel right," Ephron said of two people not immediately hooking up after they meet, explaining something has to be missing. "It's hard to make up for that."

But then Reiner changed his mind again during filming, with the new ending finding the former couple running into each other on the street, five years after the current ending, with viewers left to wonder if they might possibly reconcile. Test audiences, however, were not fans of this ending. "If they had tomatoes they would have thrown them at the screen," Andy said, with viewers wanting a happy ending. And given the fact that Reiner was happily in love after meeting his future-wife on set, he ended up giving Harry and Sally their own happily ever after, with the sauce on the side. 

26. Thirty years later, Reiner weighed in on whether or not he thinks Harry and Sally are still together. "Yes, they are," he said during a panel at the TCM Classic Film Festival. "That doesn't mean they haven't had tremendous ups and downs or been on the verge of divorce and got back together, just like any relationship. But I do think they're still together."

Just don't expect a sequel, as Crystal added, "As we got older, what would the movie about? When Harry Left Sally? When Sally Got Sick? Just let them be happy and where everybody wants them to be. For all of us who believe in happily ever after, that's where they live."

27. "Can men and women really be friends?" That was the question posed by the movie, and both stars answered while promoting the movie in a 1989 interview with USA Today.

"Yes, men and women can just be friends. I have a lot of platonic [male] friends, and sex doesn't get in the way," Ryan said. As for Crystal's answer, he said, "I'm a little more optimistic than Harry. But I think it is difficult. Men basically act like stray dogs in front of a supermarket. I do have platonic (women) friends, but not best, best, best friends."

28. One of the film's biggest supporters? The late Princess Diana, who watched the film sitting next to Crystal at the 1989 royal premiere in London, which Ryan also attended sporting almost no make-up, a baggy brown dress and then-fiancé Quaid on her arm.

Most of the crowd watched the royal react to the film, with the cast and crew worried over how she would respond to the infamous orgasm scene. "When the orgasm scene starts, she was laughing so hard, just belching it out. She had the kind of laugh where if you were on a date, you'd never want to see her again," Crystal said in I'll Have What She's Having. "Then she grabbed my hand and said, 'So naughty.'"

Diana loved WHMS so much she asked for the film at Buckingham Palace for movie nights with her friends. No word on if Queen Elizabeth II ever joined in on the fun. 

29. Another unexpected fan? Ryan's 14-year-old daughter, as then-fiancé John Mellencamp recently decided to show the teen When Harry Met Sally for the first time, Katz's Deli scene included. 

"I'm walking around the house doing other stuff," Ryan revealed to People. "But I can hear, 'Baby fish mouth.' I hear the orgasm scene, and then there's silence from the room they're watching in. My daughter's 14! And John goes, 'Meeeeeeeeg! I'm not explaining this!'"

30. But Ryan already had dealt with one of her kids watching her Katz's Deli scene, as Jack Quaid, her son with Dennis Quaid, revealed on a panel in 2018 that he had recently watched When Harry Met Sally for the first time. 

"Guys, when your mother has one of the most famous orgasm scenes of all time, you do not jump to the film, OK?" the actor said. "I saw it because I was doing a rom-com, and that's like the rom-com, and I watched it, and then afterwards I cried for so long, because I was so proud of her, and I immediately called her, and I'm like, 'I'm so sorry I missed this movie.' She's like, 'I've seen it like one time.' Anyway, that's my favorite of hers."

This story was originally published on Sunday, July 21, 2019 at 3 a.m. PT.