Taylor Swift and boyfriend Tom Hiddleston might be joined at the hip, but on Saturday night she took a brief break from their lovefest to perform with Nelly at BFF Karlie Kloss' birthday party in the Hamptons.

Karlie and pal Mike Hess (sorry, we have no clue who he is, other than being friends with Karlie's boyfriend) were celebrating both of their bdays, and this isn't the first time T Swizzle has teamed up with Nelly. Back in 2015 he joined her to sing “Hot in Herre” in St. Louis, Missouri during her 1989 World Tour.

Nelly performed “Dilemma” with Taylor, who sang Kelly Rowland’s parts in the tune. But get this -- she pranced on over to some random dude, who was NOT her beau, and planed a kiss on his cheek! What! Watch the video above...