A little more than a year after Van Halen's final show of their 1984 tour with David Lee Roth, it was revealed in a most random way that former Montrose singer Sammy Hagar would be the group's new vocalist when he was joined onstage by guitarist Eddie Van Halen at the inaugural Farm Aid on Sept. 22, 1985.

Spearheaded by Willie Nelson, John Mellencamp and Neil Young to provide relief for struggling U.S. farmers, Farm Aid was broadcast live on the Nashville Network and primarily featured country and folk acts. The guitar-driven loudness of Hagar’s music was a sharp contrast to artists like Johnny Cash, Alabama, John Denver and Tanya Tucker.

“I’m not playin’ no country up there, and I’m not adapting my set to anything,” Hagar told MTV News earlier in the day on the Memorial Stadium grounds in Champaign, Ill., where Farm Aid took place. “I’m goin’ up there and rockin’.”

And rock he did, with a cherry-red Dean guitar and headset microphone, blazing through an oh-so-'80s keyboard-heavy set featuring “There’s Only One Way to Rock,” “Three Lock Box” and the mega-hit “I Can’t Drive 55.” Following the three songs, Hagar brought out Van Halen to perform a crude and slapdash version of Led Zeppelin’s “Rock and Roll.”

Before the song even started, Hagar put the censors to the test after a fan threw a homemade sign fashioned on a bed sheet. It was too cumbersome for the singer to unravel and figure out what it said, so he called on Van Halen for an assist.

“Come on Eddie, what’s this say? Can you read?” he asked, leading Van Halen to respond something off microphone, which Hagar then repeated. “My d---’s too small? Goddamn, how’d they know that? Oh s---. Okay, well, sorry about that. Me and the old lady get along pretty good.”

At that point, TNN was getting ready to pull the plug on the broadcast because of Hagar’s obscenities, even though they had to have known it had a golden moment with two of the top figures in popular music sharing the same stage.

“We didn’t have time to work nothin’ up,” Hagar continued from the stage. “And Eddie and I were sittin’ at his house, bulls---tin’, and we looked in the newspaper, and it said Eddie was gonna jam with me. And I said, “Well, s---, I didn’t know that.” So at the last minute, we decided to go ahead and do it. We don’t know any songs as a band, so we’re just gonna jam a couple songs that we all grew up on.”

At the conclusion of “Rock and Roll,” Hagar praised Van Halen by shouting, “The king, the king,” as the guitarist went into a solo. TNN decided that would be the best time to end the broadcast, cutting away after 12 hours of performances but missing out on a major announcement: Hagar said that he had joined Eddie, his drummer brother, Alex, and bassist Michael Anthony in Van Halen.

Even though this was all before the internet, word spread quickly about the news of the mighty Van Halen's new frontman. It was the beginning of a fruitful partnership that would last a decade and produce four consecutive chart-topping studio albums before ending acrimoniously in 1996.

See Sammy Hagar and Other Rockers in the Top 100 Albums of the '90s

This Day in Rock History: September 22