Britney Spears out shopping it up in Calabasas (July 20).

The night before (Saturday), the “Piece of Me” songstress joined celebu-couple Jenny McCarthy and Jim Carrey for a fundraiser for Generation Rescue to benefit autism research.

An eyewitness told press, “She looked great and seemed really happy. She smiled and clapped during the video about autism. She was very into the information and watched a little bit of the dancers from Dancing with the Stars, sneaking out during one of the performances.”

Source: celebrity-gossip