What a week for Britney Spears. A birthday, a new CD, appearances and performances all over the world, so what a better way to top it all off with a surprise appearance at the tree lighting ceremony in L.A.?

Britney was the surprise guest who lit the tree at Nokia Theater. Her boys, Jayden and Sean were there as well as her father, Jamie.

Adam Carolla and Los Angeles Mayor Antonio Villaraigosa hosted the event. .