The two actors appear together in the sci-fi thriller, in which they must battle an aggressive extraterrestrial organism from Mars.
Although Ryan, 40, and Jake, 36, display heroic qualities in the movie they don't think they'd put up much of a fight if little green men from outer space decided to conquer Earth.
Speaking at the world premiere of 'Life', held at SXSW in Austin, Texas, Ryan - who plays Roy Adams in the film - said: "If this happened to me, I'm not qualified for this. I spent 30 minutes working on a microwave a few days ago."
And Jake - who portrays David Jordan - confirmed he'd be no good in that situation either. He added: "Seriously, I find treadmills complicated, so I don't know that I'd be able to survive on the International Space Station if a creature attacked."
But one thing that the pair did do well was have great camaraderie on set - although these elements are missing from the finished edit.
Co-star Rebecca Ferguson said: "I realized [after seeing it] that the film that I saw is not the film I shot. On set it was a sort of very homey, fun environment, a lot of jokes."
Jake agreed, describing the set "a wonderful place to be" despite the fear-filled plot.
He shared: "We were laughing all the time. None of us takes ourselves that seriously, so there was a really wonderful spirit on set all the time."
'Life' follows a team of scientists aboard the International Space Station, whose mission of discovery turns to one of survival when they begin to conduct experiments a rapidly evolving lifeform that could have caused extinction on Mars, and now threatens the crew and all life on Earth.
Director David Espinosa has likened the film to Sir Ridley Scott's 1979 sci-fi horror classic 'Alien' but pointed out one key distinction that he hopes audiences make.
He added: "The realism of ['Life'] makes it different than other movies. Alien takes place 200 years into the future - this one could take place tomorrow."
Also starring in 'Life' are Olga Dihovichnaya, Ariyon Bakare and Hiroyuki Sanada, while 'Deadpool' writers Paul Wernick and Rhett Reese penned the screenplay.