Channing Tatum.Credit : 

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Channing Tatum is getting real about the awkwardness of filming a nude scene.

During a Thursday, Oct. 9 appearance on The Tonight Show Starring Jimmy Fallon, Tatum, 45, spoke about a scene in his new movie Roofman in which he is naked in a Toys ‘R’ Us store.

In the Derek Cianfrance-directed flick, based on true events, Tatum plays Jeffrey Manchester, a thief known as the Roofman because he robbed McDonald’s restaurants by breaking in through the roofs of the fast-food establishments.

He’s caught and sent to prison — but then escapes and hides behind a display wall inside of a Toys ‘R’ Us, where he sets up a makeshift bedroom and only emerges at night. One night, when Jeffrey is cleaning himself in the sink, the store’s manager (Peter Dinklage) shows up and encounters the naked trespasser.

“I don’t care how confident you are, it’s your worst nightmare,” Tatum told host Jimmy Fallon about being naked on set. “Everyone’s clothed by the way, and you’re the only one that’s naked. That’s actually the ultimate worst nightmare.”

He continued, “Usually I have like a thong on or underwear or a sock, or something. No, this one, I show up on the day and I’m like, ‘So how are we gonna film this?’ I read over it in the script and I was like, ‘Yeah, there’s gonna be a plan for that’… [Cianfrance] is like, ‘Yeah, I don’t know.’ And I’m like, ‘What? What do you mean you don’t know how we’re gonna shoot this? And he’s like, ‘We’ll figure it out.'”

The actor explained that during the scene, he had to jump up onto a bike rack. “The camera’s like, right there,” he recalled with a laugh. “You’re right down the proverbial barrel.”

“I think I dissociated throughout the day,” he added.

The actor explained that during the scene, he had to jump up onto a bike rack. “The camera’s like, right there,” he recalled with a laugh. “You’re right down the proverbial barrel.”

“I think I dissociated throughout the day,” he added.

Tatum shared that after the movie wrapped, Cianfrance called him and asked, “So what do you want me to do with it?”

“I was like, ‘What is ‘it’?” the actor recalled. “… He’s like, ‘You know, it. Do you want me to blur it out?’… I’m like, ‘Just make it not look weird, man. Don’t make this NC-17.”

Tatum previously told PEOPLE that Dinklage was “the best partner” he could have had for his nude Roofman scene.

Asked about his favorite moments in the film Tatum tells PEOPLE, “I’m not sure if I can say running away from Peter Dinklage butt naked is the most fun. because you feel utterly exposed.”

But, he adds, “Dinklage literally was the best partner in that scene because it was just funny and fun and we’re both just making jokes the whole time.”

“It was more of knowing that the camera’s following and being right behind you, right down the old barrel, double barrel, if you will. And that was fun,” he jokes.

Tatum also said that the movie was a second chance to work with Cianfrance after passing on the opportunity to star in his 2010 drama Blue Valentine. (The male lead role ultimately went to Ryan Gosling.)

“I had just started acting and I read that script, I was just so young and new and it was such a heavy and sad, sad script,” the actor explained. “I don’t think I was mature enough to — I don’t know, I was just afraid. I just was like, ‘I don’t think I can play this, man.’”