The party-of-three attended the 3rd Annual Best Buddies Mother's Day Celebration at La Villa Contenta in Malibu.
John, 55, and Caitlin, 33, dressed Billy up in the cutest suit and sneakers for his big day out.
They showered him with tons of hugs and kisses.
Other celebs at the event included supermodel Cindy Crawford, actress Minnie Driver and sisters Nikki and Brie Bella
Caitlin welcomed Billy in April of 2018. She and John wed two months before at the Little Brown Church in Studio City, California.
John enjoyed a day with Billy at Disneyland back February. The father/son duo looked like they were having a blast at the “happiest place on earth."
What are your thoughts on John, Cailtin & Billy’s Mother’s Day outing? Sound off in the comments!