Baker Mayfield threw it all the way back to 2015 at a wedding last week... busting a move in a dance circle just like when he was a young QB hittin' the Whip at Oklahoma!!!
TMZ Sports has learned ... Baker attended his cousin's wedding in Simpsonville, S.C. on May 25 -- and he couldn't help but cut a rug when the spotlight was on the dance floor.
Check out video we obtained from the evening ... Mayfield KILLED it -- dancing along to YeahThatDJ's set at the lively function.