Impending parents are oftentimes told they’ll love their baby as soon as they set eyes on them. But, let’s be honest here, that’s not usually the case. As Kit Harington admits, “It takes time to grow love, to get to know someone.”

The Game of Thrones star got candid about new parenthood during an interview for his movie Baby Ruby, a psychological drama about the dark side of motherhood, which premiered at the Toronto Film Festival over the weekend. The actor, who welcomed a son with wife Rose Leslie last year, said that it was difficult to feel an automatic attachment to his child as a new dad.

Harington told People and Entertainment Weekly that he responded to director Bess Wohl’s work because it got at “this feeling of being told you’ll instantly love your child, you’ll instantly love this baby” when that’s not necessarily the truth.

“I knew I was going to care for the baby I had, but I don’t know whether it was instant love,” he admitted, explaining that it took him a bit to adjust to a new lifestyle.

“It was a stranger that had been planted into my house, now I had to look after the stranger, and the stranger was keeping me up all night,” he joked.

Harington, 35, said new fatherhood was a big reason why he signed on to do Baby Ruby, as it shows the life of a vlogger and influencer named Jo (Noémie Merlant) unravel after she becomes a mother. (“Baby Ruby is tantamount to a VR [virtual reality] simulation because Wohl has accomplished the goal of making the audience as uncomfortable as possible as they sit behind Jo’s eyes,” Deadline writes in their review of the film.)

“I think there was real catharsis in this,” Harington said, explaining that although the current generation of fathers are more hands on, it’s still mothers who experience true, life-altering change after welcoming a child.

“As a modern father, there is a real feeling of being a bystander at times,” the actor said. “You are not actively involved in the process of growing the child and there can be a real feeling of not knowing what is going on, what emotions are happening, what the mother or your partner is going through.”

Harington’s wife and former GoT co-star Leslie recently shared that she wasn’t “enamored” by their son at first, either. Instead, she believes new parents should be told that love doesn’t always “come innately.”

“There’s an element of me saying, ‘Hey buddy, we’re here now. It’s amazing. But I’ve got to get to know you, and forge the relationship that’s going to see us through our lifetime,’” Leslie, 35, told Harper’s Bazaar in April. “It’s something my husband also found. Once we recognized that the love gets built rather than being 100 percent there from the start, once we voiced that opinion to each other, it felt like a real release.”

Harington reassured fans that he’s currently head over heels for his little boy, who is now 19 months old.

“He’s tottering around just naming things,” he told People and EW. “He goes around saying ‘curtain’ or ‘carpet,’ he just likes impressing you with his knowledge. It’s the most astonishing thing, it really is.”

Parenthood. Astonishing, for sure.