Tickets to see comedian Louis C.K. in a pop-up show Tuesday night in Boston cost only $20 — no joke.

The comedian surprised Boston fans with an impromptu show at 8 p.m. tonight at The Paradise Rock Club.

Tickets will only be available at the comedy club’s box office, meaning you might have to take a longer lunch break to score a seat in the audience.

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C.K. announced his performance in an email to his loyal mail subscribers this morning.

"Hi there,

Tonight at 8PM (doors open at 7), I am doing a show at “The Paradise” in Boston at 967 Commonwealth Avenue. Tickets will be $20- no fees and will only be available via walk up at the Paradise box office located at the club (967 Comm Ave). They will be available from now until showtime.

To check on availability throughout the day please call 617-562-8200." 

The actor-comedian is known for his unusually low priced tickets making it easier for all his fans to afford seats in his venues.

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“For me, the bigger rooms I play and more work I get, the less I should charge. That’s just my personal formula. If I’m making more money, I can afford to charge less,” he told The Associated Press. “I always look at comedians who are not as popular as me and try to charge less than them.”

If only all entertainers followed C.K.’s rule of thumb. The actor is currently on a yearlong stand-up comedy world tour with performances in North America, Europe and Jerusalem.