Kelsey and a bunch of cast and crew members from his Netflix movie, "Like Father," hit up LONO in Hollywood for an after-party following Tuesday night's premiere. Seth Rogen -- who stars alongside Kelsey in the flick -- was also at the tiki bar, but the show belonged to Kelsey.

We're told Kelsey followed his wife onstage after she performed Dolly Parton's "Jolene" and brought the house down with his rendition of David Bowie's "Let's Dance." Watching Kelsey move to his own beat is a thing of beauty ... and even when his chops gave out, Kelsey kept going.