John Cena explains why he's moving past his fear of fatherhood, reconsidering having kids with fiancée Nikki Bella

John Cena is singing a different tune about the prospect of procreation -- a lullaby, if you will!

In the past, the wrestler-actor, 40, and his fiancée, NIkki Bella, have made no secret of his lack of interest in becoming a dad. "John doesn't want kids, so we're not going to have kids," Nikki, 34, told TMZ in April 2017. But he's now slowly coming around to the idea, he told Wonderwall.com while promoting his new comedy, "Blockers," in Beverly Hills on March 21.

"I'm actually coming more to grips with maybe giving [fatherhood] a try," he tells us, explaining that the shift is due to his growing understanding that it's okay that he might not turn out to be the perfect dad.

"It's the realization and the honesty with myself to be like, hey, this is you as a personality -- you're a tough-to-change personality. You may end up doing it wrong," he says.

The WWE star admits that when it comes to the prospect of becoming a parent, he's been deeply affected by the fear "that I would do it wrong," he says.

"That was the most intimidating aspect because I am a very driven person and enjoy being able to attack opportunities as they show up," he explains. "If you have a child, your responsibility-platform shifts. The child is now the hood ornament of that responsibility-platform. I am afraid that I would do it wrong."

In April 2017, Nikki told People magazine that John's busy schedule was to blame for his decision to pass on parenthood: "He says it's selfish but he knows that with his schedule he couldn't be an incredible father and that's why he chooses not to have kids," she said, adding that her fiance "would be an amazing dad" if he wanted to be one and that she "would be lying" if she said she didn't hope that he'd one day change his mind.

© Universal Pictures John Cena, Leslie Mann, Ike Barinholtz, Geraldine Viswanathan, Kathryn Newton and Gideon Adlon appear in a movie poster for 2018's "Blockers."

In "Blockers," John stars as the sensitive and incredibly hands-on dad of a teenager on the brink of graduating from high school. When he and the parents of his daughter's two best friends discover that the girls have made a pact to lose their virginity on prom night, the trio team up to shut down the plan at any cost. Major parenting fails ensue.

John says that if he's learned anything from the outrageous comedy -- which has a 91 percent fresh rating with critics on Rotten Tomatoes -- it's that "no one does it right" all the time when it comes to parenting.

"It's not something that you can prepare for," he tells us. "It's not something you can plan out to the letter. You can read all the books you want. And you're never done."

"My poor mother, who is 70, is still being a mom to my 36-year-old brother," he continues. "A mother's work is never done. A father's work is never done. You just need to tell yourself when [you have a kid], 'This is now my job.' Everything else falls under that umbrella."

"I'm actually getting more ready to come to that realization," he adds.

Looks like Nikki's wildest fantasies for their future together could become a reality!

"Blockers" opens in theaters on April 6, 2018.