During the actor's new interview with Mr. Porter magazine, the publication noted that Hartnett and his partner Tamsin Egerton welcomed a third child in late 2019. While chatting about his career in Hollywood -- including why he decided to take or turn down certain projects -- Hartnett confirmed the baby news.
When asked if there are any projects that he's particularly proud of, Hartnett said, "The thing I am most proud of is that I'm a father of three and I have a good relationship with my partner and a great family life."
"I'm still able to do good work and, as I've got older, the characters have become more interesting," he added.
"I don't know what the possibilities of my life could have been had I chosen different routes, but I will say that in giving in to the allure of Hollywood entirely, I know that I would not have a happy life," Hartnett continued. "I feel very strongly about that."
Hartnett, 42, and Egerton, 32, began dating in 2012. The private couple welcomed their first child in November 2015, and their second, in August 2017, per Us Weekly. Hartnett and Egerton also have yet to announce the names of their children.
Speaking to Kelly Ripa back in 2016, the "Pearl Harbor" star, who was a new dad at the time, got candid about fatherhood.
"Your ego melts away when you have a new kid," Hartnett told Ripa in April 2016. "Your heart kind of leaves your body and you give it permission to walk around with someone else for a while. It's really terrifying but it's beautiful. I love it more than anything. I wish I would have started it earlier. But I'm so glad that she is the one I'm raising."
The "Penny Dreadful" actor said his daughter changed his "perspective" on his career.
"Those moments in the middle of the night are just, like, absolutely the most precious things," Hartnett explained. "Because of her, [my] perspective shifted on work and stuff too. I used to be a little bit more precious about what I was choosing to work on because I was just so worried about how, like, my career was going to come across and stuff like that. And now with her, I'm like, 'I just got to work. I gotta make money.'"