Turning 40 never looked so fun.
Reese Witherspoon took the stage to sing “Sweet Home Alabama” with Keith Urban backing her up during her birthday bash on Saturday night.
Taylor Swift also performed at the Oscar winner’s star-studded bash inside L.A. venue Warwick.
Other celebs in attendance included Kate Hudson, Isla Fisher, Chelsea Handler, Courteney Cox, Jennifer Aniston and husband Justin Theroux.
Earlier, the birthday girl took a funny video with her mom as they got pumped up to party.