The Hills duo Heidi Montag and boyfriend Spencer Pratt flew to Vegas to celebrate the reality TV star turning 22.

The pair were in a celebratory mood as they partied at Christian Audigier The Nightclub at Treasure Island.

Heidi – who was recently pictured looking very thin, sparking rumours of an eating disorder - opted for a tight blue mini dress for her birthday outfit.

Speidi were also raising their glasses after they unveiled their very own self-portraits at Cut restaurant’s wall of fame in LA.

According to an inside source, The Hills duo were both thrilled to have their pictures on the famous wall, saying it “felt better than winning an Academy award.”

Just as well...