NOBLESVILLE, Ind. − Bob Dylan inspired Farm Aid with an off-the-cuff remark at 1985's Live Aid: “Wouldn’t it be great if we did something for our own farmers right here in America?”

Saturday night, a sold-out crowd of 22,000 at Ruoff Music Center witnessed a full-circle historical moment when the bard himself played a surprise set right before co-founder Willie Nelson's concert-ending performance. 

About 10 hours into the performances − nearly 20 acts played between 12:30 p.m. and midnight − the stage darkened dramatically before the lights slowly brightened again, revealing Dylan with members of the Heartbreakers. Crowd murmurs moved from shocked to thrilled. Clad in a black suit and white shoes, he performed "Maggie's Farm," "Positively 4th Street" and "Ballad of a Thin Man."

Dylan, who was backed by Tom Petty and the Heartbreakers when he played the inaugural event on Sept. 22, 1985, took and exited the stage without addressing the crowd.

Willie Nelson gets Farm Aid's final performance of the night

Another icon followed Dylan to end the concert. Willie Nelson played the longest and final set of the day which included "Always on My Mind," "Texas Flood" and "Mamas Don't Let Your Babies Grow Up to Be Cowboys." He delivered stunning guitar solos − as did Waylon Payne, as well as Nelson's sons Lukas Nelson and J. Micah Nelson, known as Particle Kid.

By the time Dylan took the stage, the crowd had already feasted on Neil Young's performance of his beloved song "Heart of Gold" and "Love Earth," which he called a 1960s hootenanny.

"What's your favorite planet?" he asked the crowd until everyone roared back: "Earth!"

Reminding the audience of the day's cause, Dave Matthews urged those who join the food business to pay shareholders to "go into a different line of work." He dueted with Tim Reynolds, who drew cheers for nailing a virtuosic upper-register solo in "Lie in Our Graves."

Another surprise guest, Sturgill Simpson, joined Bobby Weir and the Wolf Bros. Weir's Grateful Dead songs like "Truckin' " drew people out of their seats and into the aisles to dance. Jam band The String Cheese Incident inspired similar behavior during their time onstage.

Several Hoosier moments dotted the night. Margo Price's magnetic stage presence lit up the famous tale of Indiana boys and Indiana nights in her excellent rendition of Petty's "Mary Jane's Last Dance," for which Simpson joined her.

And John Mellencamp elicited cheers when he subbed a phrase in "Small Town" with "I was born a Hoosier right here in this state” in the midst of his driving, energetic set.

Contributing: Kim Willis, USA TODAY