Jason Segel's mom briefly stormed out of the Forgetting Sarah Marshall premiere after seeing him give a full-frontal display on-screen.

The 46-year-old actor thought it would be "one of the great practical jokes" to sit in between Jillian and dad Alvin as his composer alter ego Peter Bretter - fresh out of the shower - dropped his towel in shock after his titular girlfriend (Kristen Bell) dumps him in the opening scene of the 2008 comedy film.

In an appearance on a recent episode of the Hot Ones podcast, Jason told host Sean Evans: "I thought it would be a really, really great - like one of the great practical jokes - not to tell my parents that I did full-frontal nudity in Forgetting Sarah Marshall. And then take them to the premiere.

"This was like a really thrilling idea for me.

"And so we go to the premiere, and I had my dad on one side and my mom on the other because I always sit in between them, and it's like five minutes into the movie, my d*** comes out, and I'm like, 'Here it comes.'"

However, Jason's prank backfired.

He continued: "And I turned to my mom expecting her to be laughing hysterically, and her face is beet red, and there's a tear coming down her face."

Whispering, he added: "And I said, 'Are you OK?' And she said, 'Why didn't you tell me?' And I said, 'I thought it would be a funny joke.' And she said, 'It's not a funny joke.'

"And she got up and left the theatre."

However, Jillian's quick dash was only temporary so that she could process just what had happened.

Jason continued: "And then she came back in, and she'd, like, put herself together."

When he, Jillian and Alvin came home, she wasted no time in warning the rest of the family that Jason bares all in Forgetting Sarah Marshall.

Jason shared: "And then that night, she sent out an email to the entire family that said, 'I would like to inform you that Jason has chosen to do full-frontal nudity in his newest film. However, I'd like to assure you that it is not gratuitous and [is] essential to the plot."

Elsewhere, Jason defended his choice to do full-frontal nudity in the movie for comedy effect.

In June 2025, he told Vulture's Good One podcast: "The thing about the full-frontal nudity, it wasn't just, like, being an exhibitionist.

"It was that if the opening scene your male lead does full-frontal nudity, because it hadn't really happened at this point yet, you're forced to throw out your expectations."