Phil Vassar and Jo Dee Messina have a history of making great music together: Vassar penned two of Messina's biggest hits, "I'm Alright" and "Bye Bye." The two country hitmakers reunited at the 2015 CMA Music Festival during Vassar's show at the Riverfront Stage on Sunday afternoon (June 14).

In between bantering back and forth, he two performed "I'm Alright" (which you can watch above), as well as Vassar's 2001 hit, "That's When I Love You." See video of the latter performance below.

The two friends teased their reunion on Twitter, with Messina saying, "Can't wait @philvassar see you at riverstages @CMAFestVIP #CMAFest." Earlier, Vassar revealed via Twitter that he would be sharing the stage with the red-headed singer, calling her one of his "favorite female vocalists of all time."

This isn't Vassar and Messina's first time performing together at the CMA Music Festival. In 2008, they kicked off the four-day event with a joint concert.

Vassar's last studio album, Traveling Circus, was released in 2009. Messina just released Me last year.

Vassar and Messina aren't the only stars who shared the stage during the 2015 CMA Music Festival. Lauren Alaina and Scotty McCreery performed the Randy Travis song “I Told You So” during McCreery's fan club party, while Eric Church played with Marty Stuart and invited Chris Stapleton (along with his wife Morgane) and Phillip Sweet and Karen Fairchild of Little Big Town to sing "Girl Crush" at Stuart's Late Night Jam.

Watch Jo Dee Messina and Phil Vassar Sing "That's When I Love You":