Before a sitcom rolls tape, someone has to turn a roomful of strangers into a laughing, clapping, totally-on-board studio audience. That someone? A warm-up comedian.

Meet Mark Sweet, who’s spent nearly 40 years getting audiences hyped for shows like Cheers, Roseanne, and The Big Bang Theory.

And Joyelle Nicole Johnson shares how warming up the crowd for Patriot Act was a part of what led her to a huge stand-up career.

It’s part comedy, part crowd control, part emotional thermostat, and it might just be the most invisible job in showbiz. Until now.

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• The meteoric rise of comedian Zarna Garg
• Actors Mary Elizabeth Kelly and Dean Edwards on the art of impressions

GUESTS: 

• Mark Sweet: a veteran warm-up comedian for scripted shows including The Big Bang Theory, Full House, and Two and a Half Men. He currently does warm-up for Georgie & Mandy's First Marriage and Leanne 
• Joyelle Nicole Johnson: a stand-up comedian, writer, and actress, who was a warm-up comic for Patriot Act with Hasan Minhaj. She appeared on The Tonight Show, Late Night with Seth Meyers, and has a Peacock special called Love Joy