The only thing better than writing a Top 15 hit for a country superstar is getting to perform it alongside them in front of thousands of screaming country fans. To end a show at Southern Illinois Country Fest in Sparta, Ill. on Sunday (Oct. 7), Tim McGraw's invited 'Truck Yeah' co-writer Preston Brust of the LoCash Cowboys onstage with him to perform the popular single.

The LoCash Cowboys duo performed at the festival on Saturday night with headliner Dierks Bentley, but Brust decided to stick around an extra day to see McGraw sing their song live. And boy was he glad he did!

After meeting McGraw for the first time backstage prior to the show, the 'Truck Yeah' co-writer stood on the side of the stage to watch the star's performance. When McGraw revved into 'Truck Yeah' for the final song of his encore, he motioned for Brust to join him in front of the crowd to help him sing his current hit that is flying up the charts. Brust captured some of the footage on video, which he then shared with Taste of Country (see below).

This week, 'Truck Yeah' sits just outside the Top 10 on the country singles chart, and it's on its way to being yet another chart-topper for both McGraw and Brust. Brust and his LoCash Cowboys bandmate Chris Lucas also helped pen Keith Urban's recent No. 1 hit, 'You Gonna Fly.' Other writers on 'Truck Yeah' include Danny Myrick and Chris Janson.

Watch Tim McGraw and Preston Brust Perform 'Truck Yeah' Live