Over dinner with his 4-year-old twins, Knox and Vivienne, Brad Pitt gets personal about his family, facing his 50th birthday, and tying the knot with “Mama” (yes, that’s how the Killing Them Softly star affectionately refers to his fiancée, Angelina Jolie, 37): “The time has come…it’s soon,” Pitt says in a revealing interview in the latest issue of PEOPLE. Chatting in between bites – and pausing frequently to talk to the twins or laugh at their antics – a happy, relaxed Pitt acknowledges it’s been a big year for his “familia” since he proposed to Jolie in April. So what’s left to accomplish before he turns 50 in 2013? “I’m already doing it to an extent,” he says with a chuckle. “Let’s see what next year brings.”

Excerpts from PEOPLE’s exclusive interview with Brad Pitt below:

PEOPLE: As a longtime supporter of President Obama, you must have been happy about the election.

PITT: Yeah, me myself, of course I was quite happy about the results. Because of wedge issues, because of foreign policy.

PEOPLE: And the gay marriage initiatives you supported were passed.

PITT: Sure, I believe in it. I believe in the idea of fairness and equality in our country. I truly believe it’s a matter of time. The next generation isn’t frightened by anything.

PEOPLE: Your mom recently wrote a letter to the local newspaper supporting Mitt Romney and his stances against gay marriage and abortion. When you go home to Springfield, MO. for the holidays, is there tension around the dinner table?

PITT: Certainly we have those discussions. I come from a Christian family, and [gay marriage] goes against Christian beliefs, as far as what’s going to get you into heaven or not. My argument is, that may be as you believe, and it may be true in the end – I don’t think so – but let your God make that call, and in the meantime we live in a country where everyone should be treated equally, so let’s treat everyone equally.

PEOPLE: What’s been the highlight of your year?

PITT: …It’s been a family type of year, a down-home type of year. Mama’s worked more. And quite frankly I’ve really enjoyed it.

PEOPLE: What kind of wedding do you have in mind?

PITT: Just family. Keep it simple. Keep it simple – really.

PEOPLE: Someone’s turning the big 5-0 next year. How do you feel about it?

PITT: …I want to make sure I’m doing things of value – that mean something to me. Make sure I’m doing things I’ve always wanted to try. And make sure I’m not doing things I don’t want to do. Because I’m very conscious of time; I know it’s limited.

PEOPLE: You know you could ask your pal George Clooney for advice on turning 50.

PITT: No, no, he’s too old. We live different lives. [Laughs] What can he tell me? Other than how to protect my liver!

Brad Pitt’s complete interview is featured in the 12/10/12 issue of PEOPLE, on newsstands everywhere now.

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