Celebrity Parents John Stamos Shares Sweet Photos from Bubblefest with Son Billy: 'Celebrating Early Billy Birthday' John Stamos’ son Billy celebrates his 4th birthday on April 10 By Vanessa Etienne Vanessa Etienne Twitter Vanessa Etienne is an Emerging Content Writer-Reporter for PEOPLE. People Editorial Guidelines Published on April 7, 2022 02:09 PM Share Tweet Pin Email Photo: Emmalee Mang; Inset: Alberto E. Rodriguez/Getty John Stamos is getting an early start on his son's birthday celebrations. On Wednesday, the Fuller House star shared a series of photos on Instagram from the festivities in honor of his son Billy, who turns 4 on April 10. For the occasion, they visited Discovery Cube's Bubblefest where Billy was all smiles as he played in the room full of bubbles. The father-son duo was joined by Stamos' wife Caitlin, his sister Alaina, actor Josh Peck, and more. "Celebrating early "Billy Birthday"courtesy of his beautiful auntie @alainastamos and @thediscoverycube - We LOVED #bubblefest THANK YOU for a Wonderful Day!" the proud dad captioned the post. Billy's mom Caitlin replied in the comments, "Best Birthday Ever!❤️," while aunt Alaina added, "Love you all so much! Nothing but the best for our Billy Boy!! " Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. L: Caption . PHOTO: Emmalee Mang C: Caption . PHOTO: Emmalee Mang R: Caption . PHOTO: Emmalee Mang The Sweetest Shots of John Stamos' Son Billy Back in September, the Big Shot actor mused over how fast his son is growing up, sharing an adorable slideshow to Instagram of Billy on his first day of school. The video, set to The Beach Boys track "When I Grow Up (To Be a Man)," included several photos of Billy throughout his childhood. In the last picture, the toddler smiles on his first day of school, wearing a blue Hawaiian shirt, navy shorts, Adidas sneakers and carrying a colorful lunchbox. "First day of school. I'm not crying, you are," Stamos wrote. Stamos also spoke to PEOPLE last summer about life at home with his little boy, calling his family of three a "dream come true," especially considering the actor once believed having a family wasn't in the cards. "I always wanted to have kids, but I didn't think I'd meet the right person," Stamos recalled. "And maybe I felt like well, I have everything, I shouldn't be greedy." Ultimately, Stamos said he attributes finding his wife to "straightening up my life." Said the actor: "I wasn't deserving of it yet I think. But six years ago, I sobered up and I became a better person. And when Caitlin came around, I recognized it immediately. I said, 'I have to be good for that to make it work.' "