Becoming a dad made a man of me     The heart-throb of Bridget Jones’s Diary reveals how fatherhood forced him to grow up

On the screen, he’s every woman’s romantic fantasy—the tall, handsome hero who makes everything all right in the end. But, in real life, Colin Firth admits that has taken him a considerable part of his 45 years to even become a proper adult.

‘A lot of us actors grow up in a bit of a fantasy world, which can stunt our emotional growth,’ he confesses cheerfully. ‘We all have imaginative worlds while we’re children, and most people grow up and find their fantasy life dims a little bit as they have to deal with the realities of the world. But not us actors—we have to continue the fantasy in order to do our job.

‘I know I grew up painfully slowly. I wasn’t practical in any way and used to be untidy—really, I used to be quite chaotic. I just couldn’t be bothered with what I saw as the boring realities of day-to-day life. In fact, I was quite proud of this because I felt it was a sign of loftier thoughts!’

What made Colin finally join the real world, he says, was becoming a father. ‘I can say definitely that no single event has changed me more than having a child,’ he admits. ‘It’s the first thing to happen to me that I realised I couldn’t go back on.

‘Before I was a father, I always had the rather juvenile attitude that everything I did in life was somehow undoable—that I didn’t have to be absolutely 100 per cent committed to any of the things I said or did. I think that was an illusion because you are always committed to what you do—but, nevertheless, it was what I believed.

‘But when you have a child, it becomes very clear that this is a part of you that will be with you for a lifetime—no matter what. You can’t walk away from it. Or, if you do, then you do so at great cost.’

Colin has three sons from two different relationships. Canadian actress Meg Tilly is the mother of his eldest won, William, now 15. William divides his time between British Columbia, where Meg lives, and Britain, where he frequently visits Colin.

Ten years ago, while making Nostromo—a BBC production of the epic Joseph Conrad novel—Colin met beautiful Livia Giuggioli. They married a year later and now have two sons, Luca, four, and Mateo, two.

Being the father of three boys of varying ages means Colin has had to step into the real world with both feet.

He says: ‘I have had to learn about the real, practical world because it’s the one I share with my children. Much as I’d like to, I just can’t take them into my imaginative world with me. They don’t belong there, and it doesn’t help them.

‘And I can’t just sit around and wish them the life I want for them—I have to work to make it happen. If that is what growing up is, then that’s what’s been going on.’

The Firths must juggle their lives skilfully to keep a balance of living together in London, visiting Livia’s family in Italy whenever they are able to, and travelling wherever Colin happens to be making a film.

The family has just returned from Slovakia, where Colin was filming his role as Aurelius in The Last Legion. It’s an adventure story set at the demise of the Roman Empire. Colin approvingly describes it as ‘a time of sex and violence from beginning to end!’.

And, he says, while Mateo is too young to realise what Dad does for a living, Luca is now just about old enough to visit him on movie sets.

‘He came to see me while I was making the film Nanny McPhee, but he didn’t really have any concept of what we were doing there,’ Colin says.

‘He seemed most interested in all the cameras and cables, so we have developed the idea with him that I work with cranes and heavy machinery. He did seem to like that thought, and I don’t want to crush his idea that I do something manly with my life, instead of what I really do—putting on costumes and make-up, and flouncing around in front of the camera!’