Michael Phelps is swimming with joy over his newest family member. 

The Olympic gold medalist and his wife, Nicole Johnson, welcomed their fourth child, Nico Michael Phelps, on Jan. 16. 

"@mrs.nicolephelps and I wanna welcome Nico Michael Phelps to the world. Born on 1/16," the decorated athlete shared on Instagram Jan. 22. "We're so blessed to be given a 4th child. We're now a family of 6!"

The exciting announcement was accompanied by a photo of the couple with Nico, who was swaddled in a blanket while Phelps held him adoringly. 

Nico is the fourth kid—and fourth son—to join the Phelps family, which already includes Boomer, 7, Beckett, 5, and Maverick, 4. Michael and Nicole, who got married in 2016, first confirmed they were expecting a sixth addition to the fam in an anniversary post from October. 

"Happy Anniversary to my best friend, hubby and partner thru life," Nicole captioned the sweet tribute. "I couldn't have asked for anyone better!"

She then added, "For those that are wondering… yes! we're expecting our 4th Phelps in 2024."

Fortunately, the former Miss USA contestant has no problem being the only girl at home—according to her husband. 

"I think Nicole said something along the lines of, like, ‘I'm so lucky to have a house full of boys and no girls,'" Phelps told People in 2019, "And Boomer looked at her and said, ‘Mommy, you're the girl in our house.'"

The 38-year-old continued, "She's the queen of the household and she's the only lady in there, so she likes it, I think. She said she enjoys it."

Want more of the adorable Phelps family? Keep reading to see all their cutest moments. 

In 2017, the 15-month-old was immersed in the family business at the Huggies Little Swimmers #trainingfor2032 event in New York put on by the Michael Phelps Foundation.

Who needs a golf cart when you can hitch a ride with mom, as 4-month-old Maverick did at a tournament in Scottsdale, Ariz., in January 2020.

Beckett enjoyed a shore thing with his mom in July 2020.

Boomer practiced his "hello, adoring fans" stroke during the Men's 400m individual medley on day one of the 2021 U.S. Olympic Team Swimming Trials in Omaha, Neb.

The Phelps crew sparkled in stars and stripes on the Fourth of July.

Disneyland is always more grand with grandparents in tow. Nicole called the October 2022 excursion "the best trip I've ever had."

Merry Christmas from all creatures great and small.

There was plenty of dad to go around, as the boys enjoyed a snuggle with their 6-foot-4 father.

The Phelps family may not win any synchronized swimming medals, but those golden smiles are priceless.

Who needs a pool when you've got a whole lake?

Boomer, Beckett and Maverick bond in front of the king of all lion statues during their 2023 summer trip to the San Diego Zoo.

No running allowed by the pool, but making faces by the jacuzzi is encouraged.

Cupcakes took the cake for Maverick's fourth birthday in September 2023.

In case you didn't know who they're related to...

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