10 INSANE TV Cameos You've Never Seen
9. Conan O'Brien - How I Met Your Mother
Conan O'Brien's cameo in How I Met Your Mother's season seven episode "No Pressure" is especially hilarious - not to mention tough to spot - given that he literally doesn't do anything.
Despite being an extremely recognisable talk show host, O'Brien appears as an extra in the background of bar MacLaren's when Barney (Neil Patrick Harris) runs outside in the middle of the episode.
O'Brien can be seen stood by the door as Barney runs past, with his face visible on-screen for around a second.
As for how O'Brien ended up playing such a small "role" in the episode? He actually won the part through a charity auction, and when the show's producers found out that he was the winner, they began brainstorming ideas for him to have a fun cameo.
Yet O'Brien hilariously decided that it'd be funnier if he simply played a totally insignificant background role which most people wouldn't even notice.
The show's co-creator Carter Bays concurred, saying, "In New York, every now and then you'll see somebody famous at a bar, but nobody really makes a big deal out of it."
This isn't O'Brien's only cameo in a beloved sitcom, however. He also turned up in The Office, though that one was a little more obvious, given that he literally passes through the middle of the frame and the camera fixates on him as he walks past.