20 Most WTF Movie Cameos Of All Time

4. Judd Apatow('s Junk) - Popstar: Never Stop Never Stopping

The Lonely Island's hysterical mockumentary features a memorable sequence in which an obsessed fan thrusts his genitals up against the window of Kid Conner's (Andy Samberg) limo.

It's an hilarious moment on its own merits, but extra-funny once it was revealed online that the penis in question belonged to none other than comedy mega-producer Judd Apatow.

Co-director Akiva Schaffer explained Apatow's decision for baring all, that, "He wanted to show it because he was like, ‘I’ve had this normal but really well-proportioned dick my whole life, and I’ve never shown it. And I’m afraid I’m getting older and going to lose the bod soon'".

You can't fault the logic, WTF though it is all the same.