US Olympic swimmer Michael Phelps and his wife, Nicole, are celebrating being a family of four! The couple announced the arrival of their new baby boy in a series of adorable Instagram shots on Tuesday, and it seems that their two-year-old son Boomer already loves being a big brother.

“Magical moments yesterday,” Phelps captioned a photo of his wife and two sons cuddled up together in the delivery room at the hospital. “Nicole and I would like to introduce Beckett Richard Phelps to the world! We had a healthy baby boy and a healthy mama. I truly do feel like the happiest man in the world. Being able to build our family to now four (six with doggies) is so incredible!”

Nicole shared a similar photo that also had Phelps sneaking into the frame, and said that being the only woman in the house didn’t faze her. “I’m surrounded by boys and I couldn’t be happier,” she wrote.

Beckett joins two-year-old brother Boomer, whom the world met (and totally loved!) during the 2016 Summer Olympics in Rio. “I am officially a big bro!!!” Boomer’s official Instagram account, which was created during the Rio games, read. “All I wanna do is hold him! I can’t wait til I get to teach him so many cool things about the world!!” The photo showed Boomer holding baby Beckett (with a little help from Phelps) and looking at him admiringly.

The Phelps first revealed they were expecting their second child back in August, in a photo announcement that featured Boomer, naturally. Shortly before Phelps’ successful Rio Games, where he won five gold medals (six medals total), he and Nicole secretly wed, although the world didn’t find out until later that fall. Congrats to the growing family!

Do you follow any of the Phelps family on Instagram? Let us know @BritandCo!

(photo via Matt Winkelmeyer/Getty Images)