Nathan Fillion will play himself in an upcoming episode of "The Big Bang Theory."

The actor, well known for his role "Firefly" will guest star in the Feb. 19 episode, Entertainment Weekly reports.

"Big Bang" characters Raj and Leonard will spot the actor at a restaurant and debate whether to ask the current "Castle" star for a picture.

Fillion also had roles on "Buffy the Vampire Slayer and Dr. Horrible's Sing-Along Blog.

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