The Brit became a single dad after his marriage to Donya Fiorentino ended in 2001, but he was able to raise his youngest sons Gulliver and Charlie thanks to his flexible shooting schedule for the Potter series and Christopher Nolan's Batman movies.
He tells Britain's The Independent newspaper, ""I'd had a sort of 'domestic derailment' and then found myself with these two young boys. I felt both trepidation and a sense of excitement. And I just wanted to be there, for them.
""So actually, (the roles as) Sirius and Gordon came at a good time. They allowed me, certainly financially, to really be at home with the kids. You make a Harry Potter movie for six weeks - and some of the time they would travel with me - and then you have maybe seven months at home. It's been wonderful. They are my greatest accomplishment, terrific boys.
""I love getting them up, having breakfast and driving them to school - although Gulliver, who's 14 now and in high school, pretty much takes care of himself in the mornings. He's discovered girls, and doesn't want to be a grotty, smelly kid any more, so he's really making an effort in that department.
""And I'm an honorary mother. There's a group of friends from pre-school, we're close and still see each other... I'm one of the mums.""