U.S. Olympic champ Ryan Lochte emerged from a nightclub in London last night looking like a space oddity -- wearing a David Bowie t-shirt and a dazed expression on his face ... then stumbling into a waiting car.

Ryan had hit up a place called The Rose Club with several friends -- and left early this morning ... appearing much worse for wear.

But the night wasn't a total wash -- Lochte left the club with a couple of stunners.

This is ground control to Ryan ..

From TMZ.com

Thumbnail via TMZ.com