Celebrity Parents Gisele Bündchen and Tom Brady Celebrate Son Jack's 13th Birthday: 'So Lucky to Have You' Tom Brady shares son John "Jack" Edward with ex Bridget Moynahan By Georgia Slater Georgia Slater Twitter Georgia Slater is a writer/reporter on the Parents team at PEOPLE. People Editorial Guidelines Published on August 22, 2020 05:00 PM Share Tweet Pin Email Tom Brady and son Jack. Photo: Aflo/Shutterstock Gisele Bündchen and Tom Brady can't believe how fast their kids are growing up! On Saturday, the supermodel and the NFL star celebrated son John “Jack” Edward's 13th birthday. Brady shares his eldest child with ex Bridget Moynahan. Brady was first to pay tribute to his son on social media, posting an adorable image of the father-son duo leaning their heads on one another. "HB2U HB2U HB2 Jack HB2u," the quarterback captioned the photo. "We love you!! ❤️❤️." Several of Brady's teammates on the Tampa Bay Buccaneers, as well as former teammates from the New England Patriots, commented on the post to wish Jack a happy birthday. 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 Buccaneers player Mike Evans responded, "Happy B Day Young Jack ✊🏽," while Patriots star Patrick Chung added, "Happy birthday man!" "HBD Jack!!" replied former teammate Danny Amendola. Bündchen, who also shares son Benjamin, 10, and daughter Vivian Lake, 7, with Brady, shared her own celebratory post for Jack's special day. "Happy birthday Jack!!! I can’t believe you are already 13!! We are all so lucky to have you in our lives." the 40-year-old wrote. "Thank you for being the best big brother in the world. We love you soooo much!!! ❤️," Bündchen added, also including the caption in her native Portuguese. Gisele Bündchen Celebrates 'Sweet Dad and Loving Hubby' Tom Brady on Father's Day Gisele Bundchen/Instagram The supermodel included a sweet photo of Jack snuggling with a dog while sitting on a boat, as well as siblings Jack, Benjamin, and Vivian jumping into the water together. "Awwwww he’s the best!!! HBD Jack!!!" Erin Andrews replied. Gisele Bündchen Reveals Why She Doesn't Like to Be Called a Stepmom — and What She Prefers Instead Bündchen opened up about "being a stepmom" to Jack on her Instagram Story in February. The former Victoria’s Secret Angel told her followers that she doesn’t like using that term to describe herself when it comes to parenting. “I don’t like the word ‘stepmom,'” she shared. “I like the word ‘bonus mom’ because I feel like it’s a blessing in my life. I feel so lucky that I got to have an extra wonderful little angel in my life.” Tom Brady/Instagram Brady had just started dating Bündchen when he and Moynahan discovered they were expecting a baby together after they had already split. Moynahan told PEOPLE last April that the three of them worked hard to blend their families ever since.