Watching the CBS comedy How I Met Your Mother, one sees familiar faces like 'American Pie' actress Alyson Hannigan, Muppets star Jason Segal, and Harold and Kumar side character Neil Patrick Harris. But Monday night's episode got a special surprise visit from a famous talk show host.

Conan O'Brien was seen lurking in the background of a scene taking place in the characters' regular hangout, MacLaren's Pub, in the episode titled, No Pressure. But O'Brien's appearance is no coincidence; the TV personality won the part in a charity auction last March in support of the Ojai Playwrights Conference, reported Vulture.

According to an interview with Harris on O'Brien's show last year, the two were sitting at the same table during the California auction benefit. When the prize of a walk-on role for How I Met Your Mother was announced, O'Brien declared That's the only one I'm gonna bid on! Turns out, he was telling the truth. I kept bidding against myself, O'Brien said with a laugh when talking about the event with Harris.

If you missed last night's episode, check out the clip below.

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