Kevin O’Leary and Timothée Chalamet‘s electrifying bare-bottom paddle scene in Marty Supreme was as wild off-screen as it was on.

“We initially used a fake paddle with a hinge and a foam element, designed to be painless. But it failed immediately,” O’Leary, 71, shared exclusively with Us Weekly prior to the film’s Thursday, December 25, debut. “So we switched to a genuine wooden paddle, complete with grooves.”

O’Leary, portraying businessman Milton Rockwell in the film, revealed there was an “ass double” available for Chalamet. However, the actor insisted on performing the scene himself. The narrative involves Marty (Chalamet) seeking Milton’s forgiveness after missing exhibition ping pong matches. Despite Marty’s pleas, Milton demands the young athlete drop his pants for a spanking.

“Timmy came in and declared, ‘No, it must be my own behind. I want it immortalized on film forever,’” O’Leary recounted, noting he attempted to dissuade Chalamet once he realized he’d be using a real paddle. “But he was determined. So we started spanking, making sure to keep the redness consistent on both sides.”

Meanwhile, Gwyneth Paltrow had a humorous mix-up with Timothée Chalamet’s makeup on set. Mistaking his character’s makeup for actual skin issues, she offered some well-meaning advice. “In Marty Supreme, Timothée’s character has pockmarks, and they altered his eyes with contacts and glasses,” Paltrow, 53, explained on the December 2 episode of The Run-Through With Vogue. “It’s all just makeup.”

While O’Leary “could feel the heat off” of Chalamet’s buttocks after about “20 takes,” director Josh Safdie told the Shark Tank star he was “not hitting him hard enough” and the scene didn’t “look real.” (“Now I know you’re a sick puppy,” O’Leary jokingly remembered thinking.)

“I wound up like a baseball bat, and I nailed his right cheek, and I think his eyeballs exploded out of his head, and that’s what you see,” O’Leary said of the take used in the final edit. “His reaction to that was still just great.”

O’Leary confessed he was impressed with what a “crazy trooper” Chalamet was on set.

“I have a new respect for that kid,” he said. “There’s no question about it. And he deserves an Academy Award.”

In recent weeks, Chalamet has echoed similar sentiments about his performance, which he has deemed award-worthy. The Dune star ultimately received backlash for his confident stance, but from O’Leary’s perspective, Marty Supreme is unlike Chalamet’s previous roles.

“I went out of my way knowing I was going to be across from him to watch all his stuff, the Dune stuff, everything [is] so good. And I can tell you with certainty, and I’m right about this, this is his best performance by a factor of 100 percent,” O’Leary told Us. “It’s beyond anything he’s ever done. And he went to a new place. He just did. And I was there. I watched it happen. I was in the room, saying, ‘Wow, this guy is f***ing crazy.’”

Coming from the world of reality TV, seeing Chalamet’s process for getting into character as Marty was a whirlwind experience for O’Leary due to his ability to “riff” and “improv.”

“When I saw the final cut, they took scripted lines and merged them in with riffs that were improv, And that’s why the kinetic energy is there, the best of the best of every scene. Even though it was a mistake,” he said. “Chalamet kind of works in every scene where he gets up, comes back, sits down, and he’s in Marty, like, he’s not Chalamet anymore. He’s Marty. And the sparks are flying off him, and if you’re crossing him, you’re just going at him.”

Marty Supreme follows up-and-coming table tennis star Marty Mauser’s journey to become a professional champion, following him on his journey from the Lower East Side to international tournaments. . The sports comedy is loosely based on the career of real table tennis pro Marty Reisman.

O’Leary made his acting debut in Marty Supreme after being one of the iconic moguls on Shark Tank for nearly two decades. The business mogul explained that while he was excited to give acting a try, some of his team members weren’t sure if he could make the transition.

Timothée Chalamet still can’t believe he’s on the cover of a Wheaties box. The actor, 29, addressed his limited-edition Wheaties “Marty Supreme Box” during an appearance on the Wednesday, December 17 edition of The Tonight Show Starring Jimmy Fallon. Fallon, 51, beamed as he held up the box, which features a very serious-looking Chalamet as […]

“‘Look, Kevin, this is acting. This is a script. This is scripted. You are not a scripted guy. You’re a reality guy. We have built a big franchise with you,’” O’Leary recalled someone from his team saying. “He said, ‘I have to be transparent with you … as your representatives some of us don’t like it. We think you’re going to s*** the bed.’ Those are the words he used.”

Despite the naysayers, O’Leary was adamant he was going to try something new.

“And I said, Well how do you know I’m going to s*** the bed? How does anybody know anything until I try it?’ Because I think you want to keep your life interesting, you got to go out of your comfort zone,” he reflected, “And so they sent the script over.”

After printing out the script, one of O’Leary’s friends saw paper on the businessman’s deck and decided to read it while watching the sunrise. The pal, who was unfamiliar with Safdie’s work, was captivated by the story.

“He says, Kevin, who wrote this? What sick puppy, screwed up, crazy person wrote this?’ I said, ‘Why are you asking?’ He said, ‘This is sick. It’s sick, but I can’t stop reading it, and I can’t stop and you have to be this guy, Milton Rockwell,’” he explained. “It’s crazy … that got me because here’s some random guy, he [didn’t] know anything about the story, and he was hooked, like, just riveted. And I thought, ‘S***, this is going to be a good movie.’”

Still, O’Leary didn’t make it easy for Safdie. When asked if he could meet them in New York to discuss the project, O’Leary countered with an offer to fly to him in for a meeting at his lake house near Toronto.

Marty Supreme has an all-star lineup. The sports comedy helmed by Josh Safdie stars Timothée Chalamet as Marty Mauser, a man training to become a ping-pong player and bring the sport to new heights in the 1950s. According to the film’s official synopsis, Marty is “a young man with a dream that no one respects” […]

“I said, ‘How about [a] new idea? I’ll send a plane. You get on it, you fly up here, and we read this together on my dock with the ducks going by and the sun setting and rising, peaceful environment,” he recalled. “And I thought it was also a bit of a test to see how serious they were, because if they’re going to do that, then they must be serious. So they did it, and they came up.”

Despite being excited to take on the challenge of Rockwell, O’Leary admitted he was initially “dissatisfied” with his character’s ending — but worked with Safdie to deliver something he felt was justifying for Milton’s journey.

“If I’m really Milton Rockwell, I would never let this little f***er do this to me, and I would rip his f***ing heart out,” he quipped adding that he ended up collaborating with the writing team for a different ending. “That changed my whole view about things, because the ending we came up with on a collaborative basis. I’m not going to say I wrote it, but I told them that I was unhappy, and they gave me a path to where I was happy. And I’m very happy with the way it ends.”

Marty Supreme hits theaters on Thursday, December 25.