In attendance were Spears's 17-year-old actress sister Jamie Lynn and her baby daughter Maddie, Spears's brother Bryan, her mother Lynne and her father Jamie.
"Britney was looking on like a very proud mommy," an insider told Usmagazine.com. "She got a kick out of watching the boys in their cars and was laughing and smiling."
Sean and Jayden, Spears's children with ex-husband Kevin Federline, were given tiny sports utility vehicles for their special day, the entertainment news Web site said.
Notable deaths of 2014 [PHOTOS]