Ryan Reynolds has revealed the aspect of fatherhood that scares him the most – the passing of time.

The new dad, who welcomed his first child with wife Blake Lively earlier this year, said in an interview with AOL Build, "You suddenly feel the inexorable amount of time go by.

"There's nothing that ages you faster than having a kid, and that'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're looking at this person and time is just flying by. Like how is it possible that you're already half a year old?

"And when most people are given, at best, 90 of these years on this planet, you start to look at it like that, it freaks you out a little bit. You start to make the most of the time you have with this person."

Blake Lively and Ryan Reynolds

Reynolds added that his working lifestyle allows him to spend long periods of time in dad-mode when he isn't filming, " "We have long hours but we also get breaks, and unlike most people who get one week off a year, I might have three months off which is so nice, those three months used to drive me insane when I was a young buck, single, and carefree, but now I just want to be with my daughter so yeah, I'll do anything to be with my wife and baby."

The Woman in Gold star previously told E! News that he doesn't mind being woken up in the middle of the night by his baby girl James, "You wake up in the middle of the night, you got a big stupid smile on your face. I was telling someone else that – anything else that woke you up every 45 minutes, you'd kill it. But when it's a baby, it's the best thing that ever happened to you."

While Reynolds may be the doting dad, he isn't afraid to poke fun at his daughter on social media tweeting last month, "My daughter's only 6 months old and already drawing. I'd hang it on the fridge but honestly, it's absolute garbage."

He has also joked that his short time as a parent has made him an expert saying, "On Fathers Day, my daughter smiled at me. It was all the gift I needed as I packed a bag and left for 6 years to write a book on parenting."