John Cena Reveals the One Thing He's Learned From Portraying a Parent in 'Playing With Fire' (Exclusive)

Cena plays a fire superintendent, who along with his team of 'smoke jumpers,' rescues then must babysit three siblings.

There’s a lot one can learn from portraying a parent, but for John Cena, his latest film role taught him one powerful quality he plans to use if he ever becomes a father.

“Patience!” Cena told ET’s Nischelle Turner as she visited the actor on the set of his new film, Playing With Fire, in Vancouver, Canada. “That is the one word that I will keep repeating to myself over and over.”

“And, I think that's [a] good life lesson,” he added. “I think we could all use a little more patience.”

Cena, 42, added that W.C. Fields’ famous quote, “Never work with animals or children,” likely stemmed from “somebody who was short on patience.”

“I love animals and children are so beautiful and creative -- you just have to have the patience for it,” he said. “I don't remember what the hell I was doing at four or 10, so to be able to get someone of that age to give you a performance … our children are awesome on this movie and so were the animals.”

“You just have to understand the circumstance and manage the element and just be patient,” he continued. “That's all it is.”

While patience is a virtue that Cena’s character, Jake Carson, utilizes when he finds himself babysitting, it’s also becoming more important away from set, with the actor sharing how he often takes care of his pals' kids.

“I guess I have some friends that I would babysit [their kids] a lot more and more,” he said. “Which is weird because I didn't think that would be something I'm meant to [do.]”

So, what can kids expect from a day with Uncle John?

“I would probably ask them what they enjoy and then I would ask if there's anything they've ever wanted to do, and if it was in my realm, let them do [that,”] he said. “[Kids] will [get you out of your comfort zone] and I try to get out of my comfort zone at least once a day, so that would be a nice vehicle to do that.”

Speaking of getting outside of his comfort zone, Cena sports a different look, which he describes as “not bad,” in Playing With Fire, which hits theaters on Nov. 8.

“I've been having my hair cut [for] 20 years the same way, so it was definitely a change, but it is what it is,” he said. “It was cool because it was uncomfortable to start and I felt self-conscious about it and now I'm embracing the uncomfortable and it got me here.”

Despite the tough-guy persona that Cena is known for, he admits that his character in the movie is a whole other level of stalwart. He plays a fire superintendent, who along with his team of fire attendants known as "smoke jumpers," rescue three siblings, whom they must then take care of.

“There's no way I could train for a day, a week, a month, a year to be a smoke jumper,” Cena said. “I'd have to learn to be a firefighter first and then learn to be a smoke jumper and what they do is unbelievably tremendous, so we're trying to pay homage to them."

“No way I could do this,” he reiterated. “I will look fantastic when we [film] this, but the people who are actually the smoke jumpers who are jumping into these disasters -- they are one of a kind and there's a reason there are are so few of them.”

Jake is the boss of the smoke jumpers and while Cena didn’t want to give too much away, he teased that the character is “aspiring to be a bigger boss” and is “the most badass of the badasses .”

And, it seems the film has whet Cena’s appetite from some adrenaline-chasing, with the actor admitting it’s a big part of what he misses about his wrestling days.

“The adrenaline junkie -- I miss that,” he said. “I'm gonna get back to it as soon as I'm done with this.”

See more on Cena and Playing With Fire below.