United Kingdom, Jan. 23 -- 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 ...