NEW YORK — Celine Dion is bravely opening up about her recent health struggles.

In heartbreaking new documentary “I Am: Celine Dion,” the five-time Grammy winner gives viewers an intimate and, at times, harrowing look inside her ongoing battle with stiff person syndrome (SPS), an extremely rare neurological disorder that causes painful spasms and muscle stiffness. Dion, 56, made a rare public appearance at the film’s premiere Monday at Lincoln Center’s Alice Tully Hall, where she tearfully thanked her fans for standing by her after she was forced to cancel her Las Vegas residency and world tour.

"This is by far the biggest crowd I've had in a few years," said Dion, who announced her diagnosis in 2022. “Your presence in my journey has been a gift beyond measure. Your never-ending love and support over all these years have delivered me to this moment.”

Dion then compared herself to an apple, saying that she didn't want to make her fans “wait in line anymore if I don’t have any shiny apples for you.” But a couple days ago, “I saw a message from a fan and it said, ‘We’re not here for the apple. We’re here for the tree.’”

The singer spoke softly and deliberately for roughly 10 minutes, frequently wiping tears from her eyes. Her eldest son, René-Charles Angélil, 23, stood at the back of the stage and brought his mom a tissue midway through her speech. Dion also thanked her other “wonderful children,” twins Eddy and Nelson, 13, who were just offstage waiting in the wings. “I cannot believe how fortunate I am to have my family in my life,” she said, pausing as she was overcome with emotion.

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Dion went on to acknowledge her neurologist, Dr. Amanda Piquet, as well as the director of “I Am,” Irene Taylor: “You’ve not only made this film with such feeling and tenderness, but you also became a dear friend in this whole crazy process … as hard as it may have been at times.”

Told through new and archival footage, “I Am” is an eye-opening window into the day-to-day of living with SPS, and how the condition has affected Dion’s vocal capabilities in particular. Dion is resilient and characteristically funny, as she revisits a literal warehouse of her memorabilia and wistfully looks back on her life and career. But she also breaks down on numerous occasions, as she struggles to sing and manage her condition with the help of physical therapy and medication. The documentary’s final 15 minutes, especially, are both shocking and scary to watch, showing the devastating reality of SPS.

Dion received multiple standing ovations before and after the screening. She waved, saluted and blew kisses to the impassioned audience, many of whom could be heard crying throughout the film.

“Thank you to all of you from the bottom of my heart for being part of my journey,” Dion said before leaving the stage. “This movie is my love letter to each of you. I hope to see you all again very soon.”

“I Am: Celine Dion” begins streaming on Prime Video June 25.