The actor's daughter with wife Emily Blunt turns two next month (Feb16), and John is still adjusting to how much things have altered with parenthood. The Office star added he went through an "existential crisis" after becoming a father, details of which he didn't disclose, and he's now focused on making himself the best person he can be for Hazel.

“I went through some really serious stuff,” he told People. “There is a mirror that is held up to me now. You have someone watching you. You have to lead by example. I'm focused on becoming a better person every single day.”

John and Emily have one of the happiest marriages in Hollywood. And the actor knows how lucky they are to have found each other in the crazy celebrity world.

“I got to understand my parents better. I got to understand my wife better,” John said of how his life has changed with fatherhood. “I got to understand how lucky I am to be in the fox hole with someone I can rely on 150 per cent.”

John isn't the only one to have waxed lyrical about baby Hazel. Emily, who is currently filming movie The Girl on the Train, told the British edition of Harper's Bazaar back in 2014 that her priorities in life had dramatically switched since having her baby girl.

“Everything has slowed down," she said. "You realise that nothing else really matters. This industry, this town especially (Los Angeles), can make you feel that all that stuff matters; this rather transient world and the gush and the work and the success and the competition.

"You can get drawn into that bubble, of thinking it all matters. Having a baby has made me realise that it doesn’t. None of it. It really doesn’t.”