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OTRC: Stephen Hawking demonstrates comedy chops on 'The Big Bang Theory'

Stephen Hawking and Jim Parsons appear in a still from an April 2012 episode of 'The Big Bang Theory.' (Sonja Flemming/CBS)

"The Big Bang Theory" landed their dream guest star on Thursday when physicist Stephen Hawking appeared on the CBS series.

"When people would ask us who a 'dream guest star' for the show would be, we would always joke and say Stephen Hawking," executive producer Bill Prady said in a statement when Hawking's appearance was announced in March. "In fact, we're not exactly sure how we got him. It's the kind of mystery that could only be understood by, say, a Stephen Hawking."

"The Big Bang Theory," depicts the quirky lives of four young, nerdy physicists. Kaley Cuoco portrays their neighbor Penny, who works at the Cheesecake Factory and often helps the physicists with their love lives.

Hawking, a 70-year-old British physicist, is almost completely paralyzed by motor neuron disease and is only able to speak through a computer-generated voice synthesizer.

In the episode, Howard (Simon Helberg) gets to work with Stephen Hawking and subjects Sheldon (Jim Parsons) to several humiliating acts before he will let Sheldon meet his hero and give him his thesis paper. When Hawking comes to compliment Sheldon on his work, the humiliation continues when he points out a "boner" of an error in Sheldon's thesis.

Hawking has made guest appearances before on "Star Trek: The Next Generation," "Futurama," "The Simpsons" and "Masters of Science Fiction," always portraying himself.

"The Big Bang Theory" was nominated for a 2012 Screen Actors Guild award for Outstanding Performance by an Ensemble in a Comedy Series. In January 2011, it was announced that the show would be renewed for at least three more seasons and will run until at least 2014.

The cast members have also been making headlines of their own - Kunal Nayyar, who plays Raj Koothrappali, married former Miss India Neha Kapur in December of last year. Helberg, who portrays Howard Wolowitz, 31, on the comedy series is expecting his first child with wife Jocelyn Towne, the actor's rep confirmed to OnTheRedCarpet.com on January 27.

Watch a clip from Stephen Hawking's appearance on "The Big Bang Theory" below. You can also watch the entire episode on the network's website.

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