Michael Phelps says he will soon be a dad.

The 18-time Olympic gold medal swimmer announced his coming parenthood in an Instagram post on Wednesday.

In February, Phelps was engaged to Nicole Johnson, a former Miss California. That announcement also came on Instagram.

She said yes¿¿¿¿¿¿¿¿¿¿¿¿ @nicole.m.johnson. (Photo credit to @arschmitty )

A photo posted by Michael Phelps (@m_phelps00) on

Phelps’ agent, Drew Johnson, confirmed the couple was expecting a child.

Phelps is in the midst of a comeback to swimming. He was dominant in winning the 200-meter individual medley this past Saturday during the three-day Arena Pro Swim Series.

"I'm happy that I was about where I was at the end of last season before nationals," Phelps told reporters.

Phelps finished second in the 200 butterfly and third in the 100 fly earlier in the week.

Also last week, he was the subject of a Sports Illustrated story in which he said he was "in a really dark place” and thought about "not wanting to be alive anymore” after he was arrested for drunk driving in September 2014.

Baltimore Sun reporter Childs Walker contributed to this article.