Willie Nelson led the way for another installment of his traveling Outlaw Music Festival this past Friday night, when he brought the show to the Riverbend Music Center in Cincinnati, OH, and treated the crowd to a special collaboration, welcoming fellow Outlaw Fest headliner Sturgill Simpson for a run of songs. 

As Rolling Stone reports, Simpson first came out for Nelson’s classic “Mamas Don’t Let Your Babies Grow Up to Be Cowboys,” which the country legend first recorded with Waylon Jennings in 1978. Nelson and Simpson traded off verses with gusto, and the crowd joined in on the iconic chorus. 

Simpson then stayed on stage throughout the remainder of Nelson’s set, including for a closing medley featuring “Will the Circle Be Unbroken,” “Living in the Promiseland” and “I Saw the Light.”

Watch fan-shot video of the collaborations below. Next up for Nelson and his Outlaw Music Festival is a show in Little Rock, AR, this Friday, June 29.