LOS ANGELES, Feb. 2 (UPI) -- Nathan Fillion will appear on The Big Bang Theory.
The 43-year-old actor will guest star as himself on the CBS sitcom's February 19 episode, Entertainment Weekly exclusively reports. The network confirmed the news by re-tweeting the article Monday on Twitter.
The episode will see Raj (Kunal Nayyar) and Leonard (Johnny Galecki) spot Fillion at a restaurant and debate whether to approach him. Sheldon (Jim Parsons) is a fan of the actor's series Firefly, and frequently references the program on the show.
Fillion is known for portraying Malcolm on Fox series Firefly, and reprised the role for sequel film Serenity. He also appeared on Buffy the Vampire Slayer and Desperate Housewives, and currently stars as Richard Castle on ABC crime drama Castle.