With her custody battle finally over, Britney Spears made her first appearance at a social event in a long time, surprising everybody when she showed up at Jenny McCarthy and Jim Carrey's fundraiser for Generation Rescue.

The organization is dedicated to researching autism, attempting to “share the truth with families about the potential cause of their child’s Neurological Disorders so they can focus on effective treatments.”

A person attending the party told People magazine that Britney “looked great and seemed really happy.”

Although she stayed close to her assistant Brett and remained silent most of the time, she “smiled and clapped during the video about autism,” the witness said.

Last week, Britney Spears reached a custody agreement with ex-husband Kevin Federline. While he got sole custody of the children, Britney gets three visits a week, including two overnights, from her two sons, Sean Preston, 2 and a half years old, and Jayden James, aged 1 year and a half. Also, the settlement says Britney has to pay Federline $20,000 a month in child support, an increase from $15,000.

Other celebrities who attended the fundraising event were Hugh Hefner and the three Girls Next Door (Kelly Madison, Kendra Wilkinson and Bridget Marquardt), as well as newlyweds Charlie Sheen and Brooke Mueller, and Robert Rodriguez with Rose McGowan, who kissed and danced a lot, People informs.

Global Health Trax President & CEO Tom Dixson told the media that he greatly praised and admired the initiative of Jenny McCarthy, and the autism community.