
It all went down at Hurley's Saloon on Sunday night ... after a performance of the cross-dressing play "La Cage aux Folles."
Kelsey rolled over with his new fiancee ... grabbed the mic from a drag queen named "Lilly" and belted out the James Taylor classic, "Don't Let Me Be Lonely Tonight."

For the record ... Grammer was wearing men's clothing during the performance -- and he NAILED the song!









