Brad Pitt** is 365 days away from the half-century mark!

The Killing Them Softly star celebrates his 49th birthday on Tuesday Dec. 18 -- and although his exact whereabouts are unknown, chances are he's celebrate his latest birthday with fiancee Angelina Jolie** and their six kids.

But it's his next birthday -- the big 5-0! -- that has Pitt slightly preoccupied, he recently admitted on Good Morning America.

"I've given a lot of thought to it," Pitt said. "You become very aware of time and also, being a father, everything is time allocation for me now," added the star, who shares Maddox, 11, Pax, 9, Zahara, 7, Shiloh**, 6, and twins Vivienne and Knox, 4, with his wife-to-be Jolie, 37.

Pitt continued that, as he ages, his priority has shifted to "making sure I spend my time wisely and doing the things that are important to me and spending the time I need to with my family."

Pitt and Jolie are sure to squeeze in some family time come Christmas Day -- even though the patriarch isn't "real big on the whole Santa thing," he said recently. "What I tell the kids is some people believe it's Santa, and some people believe it's parents, and you get to believe whatever you want," Pitt said.

Still no word yet on when Pitt and Jolie, who became engaged earlier this year, will walk down the aisle.

"I certainly don't know what the new year is going to bring!" he said last month.

This article originally appeared on Usmagazine.com: Brad Pitt Turns 49: I Plan to "Spend My Time Wisely"