life must be pretty funny when you’re married to a comedian like John Mulaney — and according to actress Olivia Munn, one mix-up ahead of their engagement is pretty hilarious in retrospect.

The Your Friends and Neighbors actress, who’s been a TODAY co-host the week of March 31, visited The Tonight Show Starring Jimmy Fallon on April 2. In addition to providing an update on the eldest of her two kids with Mulaney,  3-year-old son Malcolm Hiệp Mulaney (he’s very into musical instruments, despite not being able to *play* them yet), the actress shared a very funny story about how she thought she was helping Mulaney preserve his secret proposal plans.

Explaining that they had a “very small wedding” in 2024 over Fourth of July weekend, Fallon asked her how the proposal went. “You can tell me,” Fallon joked to Munn. “I won’t tell anyone, I promise!”

Why Olivia Munn lied to John Mulaney about a friend’s marriage

“Okay, well, my best friend Corinne — my best friend since I was 13 years old — she texted me and she says, ‘Hey, are you alone?'” Munn began. “And immediately I turned to John and say, ‘Oh, my God. Corinne just asked if I’m alone. She wants to tell me something really interesting, I’m going to go call her.’ So I immediately betray her by telling him that she wants to talk alone.”

“And when I go in the other room and call her, she says, ‘Um, hey, so John called me. He doesn’t want me to ask you directly, but is there anything that you want for your proposal?” Munn continued. “I’m freaking out, though, ’cause I just told him that she called me and she wants to talk to me. And I’m like, “Oh, no! Now Corinne’s going to get in trouble.'” That’s when Munn realized she’d told her friend she was alone, when in fact Mulaney was in the next room fully aware they were on the phone together.

“I said, ‘I don’t want anything big, no friends or family, just like very simple,'” Munn recounted. But after the call, Mulaney wanted to know what she and Corinne talked about. Explaining that she “panicked,” Munn opted for a whopper of a lie. “I said, ‘she’s having…really bad trouble in her marriage.'”

Olivia Munn during an interview with host Jimmy Fallon during The Tonight Show Starring Jimmy Fallon Season 12, Episode 95 on April 2, 2025. Photo: Todd Owyoung/NBC

“And he goes, ‘What? But we just saw her and Chris the other day. They were doing great!’ I go, ‘Yeah, it’s…really, really bad.’ And he goes, ‘Well, what’s going on?’ I say, ‘They’re not having sex. It’s been six months.'” (Cue the sad trombone from a member of The Roots). “He was like, This is insane!”

Except, to make the situation even more of a sitcom plot, Mulaney knew this was all a ruse the entire time.

“After he proposes, he says to me, ‘Hey, I want you to know, I know that whole thing about Corinne, and her sex life and all that, was a lie,'” Munn said. “And I’m so embarrassed that I triple down and go, ‘No, no, no, it is true!'”

“This is how I’m starting off my marriage,” she laughed, as Fallon added, ‘You’re lying, and you’re doubling down.”

John Mulaney and Olivia Munn attend the 2025 Vanity Fair Oscar Party on March 2, 2025 in Beverly Hills, California. Photo: Amy Sussman/Getty Images

Ultimately, Munn apologized to both of them for her tangled web. “Now I understand, when people commit crimes and confess decades later, after they’ve gotten away with it and you’re like, ‘Why would you go turn yourself in?’ The guilt was too much,” she told Fallon.

Watch Munn’s interview — in which she tells a second story about her good intentions going wildly wrong — above.