Jelly Roll Chokeslams Austin Theory at WWE SummerSlam

If Jelly Roll ever wants to leave his music career behind, he's got a future in wrestling ... 'cause the singer executed an epic chokeslam at WWE SummerSlam!!

The "Liar" crooner -- who was the guest musical performer for Saturday night's event at Cleveland Browns Stadium -- faced off against the A-Town Down Under tag team ... after Austin Theory and Grayson Waller trashed the home crowd and name-dropped JR in the process.

But to the duo's surprise, the 39-year-old artist didn't take the diss lightly ... as he snuck in the ring from behind and hit both guys with a steel chair.

JR got huge props from The Miz and R-Truth, who were in the process of announcing the main event before the chaos broke out.

JR wasn't done there ... as he then grabbed Theory by the throat, lifted him several feet in the air and slammed him into the canvas.

To complete the beatdown, Roll, Miz and R-Truth paid homage to John Cena by executing the legend's Five Knuckle Shuffle and dropping his entire body to the mat.

The crowd lost their minds, and as soon as JR got back to his feet (with the help of Miz and R-Truth) ... he joined in on celebrating a job well done.

Roll went to social media after the night was over ... thanking WWE for helping him live out a childhood dream.

He wasn't the only big name in attendance ... as Machine Gun Kelly also showed up for Logan Paul's match against LA Knight -- and even loaned him a pair of brass knuckles during the action.

But it wasn't enough to help the Maverick retain his United States Championship ... as Knight ended his 273-day title run.