Timothée Chalamet insisted on being spanked for real by Kevin O'Leary in 'Marty Supreme'

• Timothée Chalamet insisted on being spanked for real in a scene in "Marty Supreme."
• Kevin O'Leary told Business Insider he used a real ping pong paddle in the scene.
• O'Leary said the take where he hit Chalamet the hardest was used in the movie.

In "Marty Supreme," Timothée Chalamet plays a ping pong hustler who will stop at nothing to get his way. On the set of the Josh Safdie film, the star was similarly determined to get the right shot — even if it meant withstanding some physical pain.

Near the end of the movie, Chalamet's character Marty Mauser begs business tycoon Milton Rockwell (Kevin O'Leary) to front the money for a table tennis rematch in Japan against his rival Koto Endo (real-life table tennis champion Koto Kawaguchi). After Mauser initially declined Rockwell's gracious offer earlier in the movie, the businessman won't let him off easy this time. Rockwell agrees to hold the match — but only if he can first cut Mauser down to size. How? By spanking him.

Mauser reluctantly agrees. He drops his pants and bends over a chair as Rockwell, surrounded by party guests, spanks Mauser's bare bottom with a ping pong paddle.

O'Leary told Business Insider that Chalamet insisted on actually being spanked in the scene.

"We had a stand-in ass and a fake paddle that supposedly would not put the full force," O'Leary said. "All of a sudden, Chalamet came on set and said, 'No, if this ass is going to be immortalized, it's my ass.'"

The "Shark Tank" star said he was stunned and tried to talk Chalamet out of it.

"I said, 'Look, man, your ass is gonna be blistered, let the stand-in ass do it,'" he recalled. "He said, 'No.' I said, 'I can't hold back, I'm gonna have to whack your ass.' He said, 'I don't give a shit.'"

O'Leary said the fake paddle broke on the first hit, so he had to use a real ping pong paddle on Chalamet's rear end.

O'Leary estimated he spanked Chalamet "more than a dozen" times while filming the scene.

"Josh kept saying, 'Harder! Harder!'" O'Leary said, referring to director Josh Safdie. "And the one where you see Chalamet's face explode, I really whacked his ass. That's what is in the movie."

The pain might have been worth it. "Marty Supreme" had the largest pre-theater average of the year ($145,000) when it opened in limited release last weekend. That's also the biggest average for any movie since 2016 and the largest ever for its distributor, A24.

"Marty Supreme" opens in wide release on Christmas Day.