Michael Phelps is a father, so the world’s greatest swimmer can now begin his work toward becoming the world’s greatest dad.

Phelps and fiancee Nicole Johnson welcomed their first-born, Boomer Robert Phelps, into the world Thursday night, and the most decorated Olympian in history called it the “Best feeling I have ever felt in my life!!!”

Phelps announced the birth, which took place in Arizona, where he trains, Saturday afternoon on Instagram. According to the Associated Press, the newborn Phelps’s middle name was given in honor of Bob Bowman, who has been Phelps’s only coach in his long and illustrious career.

Although the couple did not reveal the name until after Boomer’s birth, Phelps had said previously that the couple selected the baby’s name ahead of time.

“It’s something we both agreed on. Thought it was different,” he said at a meet in Mesa, Ariz., in April.

At the same meet, Phelps reportedly sought parenting advice from fellow Olympian Dana Vollmer, who made her return to swimming last summer after giving birth to her first child.

“It will be good for him, like it is for me,” Vollmer said. “Michael and Nicole will be good parents.”

Phelps was training at altitude in Colorado Springs as recently as Wednesday, when he conducted a Facebook Live session from the pool deck at the Olympic Training Center, but flew home to Arizona ahead of Thursday’s birth.

Posted by Michael Phelps on Wednesday, May 4, 2016

The 22-time Olympic medalist had been scheduled to swim in Atlanta next weekend in what would have been one of his final preparation meets ahead of this summer’s U.S. Olympic Trials, but Phelps told organizers that he would be withdrawing in order to be in Arizona for the birth of his son.

With limited opportunities to compete before Trials, Phelps could potentially re-enter the meet or, instead, choose to participate in USA Swimming’s Pro Swim Series event in Charlotte the same weekend.