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The Big Bang Theory's 19 greatest guest stars ranked: Leonard Nimoy, Stephen Hawking, Carrie Fisher and more
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The Big Bang Theory': 23 Most Memorable Guest Stars, From Stephen Hawking to Carrie Fisher (Photos) - TheWrap
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Sarah Michelle Gellar Guest Stars in 'Big Bang Theory' Series Finale: How This Surprise Happened! (Exclusive) | Entertainment Tonight
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