Michael Phelps is now officially a father.

The highly-decorated swimmer and his fiancée, Nicole Johnson, welcomed their son, Boomer Robert, into the world on Thursday. Over the weekend, Phelps shared photos of his newborn son on his official Instagram account.

Phelps, who will take part in the Rio Olympic Games this summer, also noted that Johnson is healthy and feeling fine after giving birth just in time for her first Mother's Day as a parent.

The happy couple revealed they were expecting back in November once the pregnancy was 12 months along. Phelps and Johnson have been dating since 2007 and he popped the question to her back in February.

A photo posted by Michael Phelps (@m_phelps00) on May 7, 2016 at 10:22am PDT

Boomer Robert has some amazing genes as not only is Phelps the most-decorated Olympian of all time -- with 22 medals, 18 of which are gold -- but his mother is successful in her own right. Johnson is a model and beauty queen, and was crowned Miss California in 2010 and placed in the Top 10 in the Miss USA pageant that same year.

Phelps has taken on a lot of responsibility lately and he noted in 2015 that he was quitting drinking until after the Olympics. Now that he has a newborn son, that vow may be taken a step further.

"Before I even went to court, I said to myself that I'm not going to drink until after Rio -- if I ever drink again," Phelps told The Associated Press last August. "That was a decision I made for myself. I'm being honest with myself. Going into 2008 and 2012, I didn't do that. I didn't say I was going to take a year off from drinking and not have a drink."

While his vow was met with some snarky reaction on Twitter, Phelps was committed to changing his habits leading into the Summer Games in Rio de Janeiro.

"If I'm going to come back, I need to do this the right way," Phelps said. "I've got to put my body in the best physical shape I can possibly get it in. Is it a challenge? No. I go to bed earlier. I sleep more. I wake up every day and have a completely clear head. I don't feel like my head went through a brick wall. There are so many positives to it."

Phelps took yet another positive step in his life by welcoming his first child into the world -- though sleeping more may be an issue.

For more content, follow us on Twitter @SportsWN or LIKE US on Facebook.