Chris Stapleton brought out surprise guest Willie Nelson — the artist responsible in part for putting Austin City Limits on the map — during his Friday night headlining set at the ACL Festival.

The two singers first teamed up for a take on “Whiskey River” — reprising their duet from Nelson’s Rock and Roll Hall of Fame induction ceremony in 2023 — before closing out Nelson’s cameo with a rendition of his “Bloody Mary Morning.”

Stapleton and Nelson have a frequently shared the stage over the past decade, including a oo-headlining stint on the Outlaw Country Music Tour. Stapleton has also popped up at Nelson’s Fourth of July Picnics in years past, 

Nelson’s ACL appearance comes less than a week before the country legend takes the stage at Austin’s Long Center for a special concert marking the exact 50th anniversary of his performance on the first-ever episode of Austin City Limits on October 17, 1974.

“There would be no Austin City Limits without Willie Nelson – simple as that,” longtime ACL executive producer Terry Lickona said in a statement. “He launched ACL into the television universe in 1974, and has helped keep us going for 50 years.”

The outdoor concert at Austin’s Long Center was free to the public via registration. The show will also livestream on Oct. 17, with highlights from the 50th Birthday Bash airing on Austin City Limits in early 2025.