Chelsea Kane joins in the celebration with Stephen Colletti as they party at 1 Oak in Las Vegas on Saturday night (February 11).
The One Tree Hill costars and off-screen couple dined at the Stack Restaurant & Bar before heading over to 1 OAK with a group of friends which included OTH creator Mark Schwahn.
PHOTOS: Check out the latest pics of Chelsea Kane
Stephen was even treated to a 3-tiered Jean Phillippe birthday cake with “Happy Birthday Stephen Colletti” written on the side. Yummy!