(Hall/Pena/PacificCoastNews.com)

You have to do a double take when you see comedian Robin Williams standing next to Radioman.

The two posed outside the IFC Theater in New York City Thursday at the premiere of the new documentary about the former homeless man turned celebrity friend. Radioman rocked a beard that was eerily similar to the one Williams had last year.

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Radioman, whose real name is Craig Castaldo, is famous in New York City for hanging around film sets and befriending numerous celebrities, including Williams. He has had a number of cameos in big time films, including 1998's "Godzilla," "Little Nicky" and "Elf." Most recently, Radioman scored a recurring role on "30 Rock."

The name "Radioman" comes from the radio he wears around his neck while he bikes around New York.

Williams, 61, also performed comedy Thursday night at the Stand Up for Heroes event, which benefited military veterans and their families.