Brad Pitt is ''surprised'' by how much marriage has changed his relationship with Angelina Jolie.

The couple - who raise six children, Maddox, 13, Pax, 10, Zahara, nine, Shiloh, eight and twins Knox and Vivienne, six - tied the knot in August after nine years together and although the 'Fury' star didn't expect things to feel any different between them, he says the ceremony has changed how he feels about his family.

Speaking to HELLO! magazine, he said: ''We have six kids so we felt beyond marriage already. But the kids were asking and we thought it would be a lovely thing to do, for them and for us as a family and it was all of that.

''But I was surprised afterwards at the effect getting married has had on us - it was more than just a ceremony, it meant a real depth of commitment. I feel like a married man - I really do.''

Despite being 12 years older than his wife, Brad insists the couple don't notice the age difference and says he didn't care about turning 50 last year.

He said: ''We're probably around the same age maturity-wise - that's the way it works with men and women right?

''But I don't feel any different for having turned 50. I've never been one of those guys who counts time or thinks about the five-year plan or the 10-year plan.

''I'm pretty clear about how I want to live my life and what I want for my family and my wife and kids and that determines how I feel.''