Ryan Reynolds on What Freaks Him Out About Being Father

"There's nothing that ages you faster than having a kid," he said.

"You suddenly feel the inexorable march of time go by," he said. "It's not because you wake up in the middle of the night every five seconds because someone's got to s--- themselves. It's really because you are looking at this persona and time just starts flying by, you just think 'like how is it possible that you're already half a year old?'"

The new movie "Self/Less" stars Reynolds as a man facing death and using the body of a younger man to stay alive, even if he doesn't know it.

"When most people are given at best 90 of these years to be here this planet, you start to look at it like that and it freaks you out a little bit," he continued about fatherhood. "You start to make the most of the time you have with this person."

He said it was the first day, which was a table reading, and she leaned over to him and said, "Ryan, I am so f------ nervous."

"And I'm like, 'Helen, you're Helen f----- Mirren!'" he said. "'Get it together!' ... I'm never going to forget this moment. I'm sitting next to one of the greatest actresses. ever and she's nervous. It was beautiful."