When Leonard from the CBS hit the Big Bang Theory shows up onstage as your drummer, you're going to get a few questions. Randy Houser was gracious enough to explain how, why and "what the heck?"

The actor's most recent appearance was Houser's show on June 10 in Buffalo, N.Y. Johnny Galecki plays Dr. Leonard Hofstadter, and before that, David on Roseanne. It turns out he's a pretty good drummer, according to the country singer.

"Johnny has become one of my dear friends and a lot of times when he gets through taping he'll just jump on the bus and go ride with me for a few days," Houser told Taste of Country during a stop at Country Jam in Grand Junction, Colo.

"At first he was a little bit shy about it, but I was like, 'Get your ass up here.'"

Galecki is not Houser's permanent drummer, and he's not about to give up his full-time job to chase music. Houser is working full-time on a new album, however. During his set at Country Jam 2017 he played several new songs, including "You Should Be Mine," "High Times" and a travelin’ tune about leaving “no stone unturned / No turn unstoned.” Galecki joined Houser for "You Should Be Mine" earlier this month in Lansing, Mich.

Fired Up is the singer's most recent album, and before that, the gold-certified How Country Feels. He told Taste of Country that he recently cut nine new songs, but has spent the last several months writing.

See Photos from Randy Houser's Set at Country Jam