Four months after reports confirmed their relationship, comedian John Mulaney and actor Olivia Munn are expecting their first child together.

Mulaney, 39, casually revealed the pregnancy Tuesday on "Late Night With Seth Meyers," during which he also opened up about his romance with Munn, 41, and his recent relapse. (Late last year, Mulaney joined "Late Night" as a staff writer.)

The comic's announcement comes four months after his divorce from a "heartbroken" Anna Marie Tendler, an artist to whom he was married for nearly seven years. Shortly after their split, dating rumors began to swirl around him and Munn.

"I packed a lot into this ... is it September now?" Mulaney told Meyers on Tuesday. "I went to rehab in September [2020]. I got out in October. I move out of my home from my ex-wife. ...

"In the spring, I went to Los Angeles and met and started to date a wonderful woman named Olivia. I got into this relationship that's been really beautiful with someone incredible ... and we're having a baby together. ... I was nervous when I was about to say the news."

Mulaney also mentioned that he relapsed on drugs after hosting last year's Halloween episode of "Saturday Night Live," and — following an intervention by Meyers, Fred Armisen and other friends — returned to rehab. He was most recently discharged from treatment in February.

"When I opened the door, I knew right away it was an intervention, which means that's how bad of a drug problem I had," Mulaney said.

"I remember saying to all of you, 'Before you all read your letter, I have a drug problem, and I need help.'"

In a full-circle moment, Mulaney recalled first meeting Munn at Meyers' wedding to human rights attorney Alexi Ashe in October 2013.

While gushing over his new girlfriend, Mulaney credited the "Gateway" star with holding his "hand through that hell" that was becoming sober.

"You guys saved me from drugs, and Olivia and this baby have helped save me from myself in this early journey out of recovery," he said at the end of Tuesday's show. "I don't have a joke for that. I'm really grateful to you, buddy."