Brad Pitt admits his attitude to his career changed when he became a father.

The 48-year-old actor - who raises six children, Maddox, nine, Pax, six, Zahara, five, Shiloh, five, and two-year-old twins Knox and Vivienne with his long-term partner Angelina Jolie - says his attitude to his work was altered by his kids because he wants to make films they can be "proud" of.

He said: "The biggest change for me was being a dad. That changes everything.

"I'm aware of the impermanence, now that I've got a few (movies) left - and I want to do stories where I can make a difference. I want them to be proud of their dad in the end."

The 'Tree of Life' star is acutely aware of the effect his and 36-year-old Angelina's high-profile careers could have on their brood and as well as not telling their kids what they do for jobs he also doesn't bring home any frustrations from work.

In an interview with the Daily Telegraph newspaper, he said: "It's so obvious for me that, when I come home, my kids are so aware of everything that's going on. It's quite important to me not to put my frustrations on them. I want them to be free, not encumbered with my junk."