The film reunites Reynolds with Deadpool screenwriters Rhett Reese and Paul Wernick. And Gyllenhaal says that the script left him "legitimately terrified". But both actors say they were drawn to the project because it was just a big, fun movie. "It felt like blasphemy that we were having such a good time," Gyllenhaal laughs. "It literally felt wrong that you could have so much fun making a movie that is as terrifying as it is."

Jake Gyllenhaal And Ryan Reynolds in LifeJake Gyllenhaal And Ryan Reynolds in Life

On the press tour, they have been putting on a riotously entertaining display of their new bromance. "I love this person as an artist," Reynolds says of Gyllenhaal. "Like, I truly am genuinely a biggest fan. So it's like one of those milestones. You go, 'Oh, I get to work with someone I admire. Someone who does things that I wish I could do.'"

He also says that he and Gyllenhaal got on so well that they were always in trouble for goofing around on set. "There were times that the producers had to go, 'Separate them. Now!' to the director," Reynolds says. "And he would be like, 'Okay. You guys just go in separate ways for awhile. Take a breather.'"

More: Read our review for Life

Gyllenhaal did manage to see the serious side of the film's premise. "I think the world is in a bit of turmoil," he says. "And our fascination with sci-fi is that it is a boundary-less world where we can kind of create what we believe to be as opposed to the reality that is. And it seems like we are headed into the unknown in a lot of ways and I think it is terrifying and exciting for a lot of people."

So Reynolds thinks that making a movie like this required some extra laughter on-set. "I wore the big extravehicular activity space-walk suit," he says, "which was a good 50, 60 pounds. And then you have to pretend that you're weightless! That was an athletic exercise unto itself, but cool. You have a moment of that wish-fulfillment, 'I'm a kid again, holy sh*t, I'm wearing a Nasa-sanctioned astronaut suit!' It was great. But then my 3-year-old daughter saw me in the spacesuit. We did a fitting in the little apartment we were renting in London and it terrified her. She had no idea why Daddy was trapped inside a marshmallow! As if I actually sewed together 700 marshmallows to get a rise out of her."

Watch the trailer for Life: