The couple will share the occasion with the actor's parents Bill and Jane who will mark their golden wedding anniversary on the same day.
There will be a huge family party at the pair's 35million-pound French retreat after they tie the knot.
"They thought their kids would love the idea of seeing mom and dad get hitched followed by a big bash for them as well as 'Meemaw and Grandpa' as they call Brad's folks," the Daily Star quoted a source as saying.
Between 200 and 300 guests including George Clooney, Matt Damon, Johnny Depp and Tom Cruise are expected to join the festivities at 35-room Chateau Miraval near the village of Correns in the south of France's Aix-en-Provence wine country.
Jolie adores her Pitt's parents and the source said, "She came up with the idea of making it a real family celebration by merging Bill and Jane's special day with theirs.
"Brad's family mean a lot to Angelina, especially since she lost her own mum Marcheline to ovarian cancer more than five years ago and spent years refusing to talk to her father," the source added.
The actress has reconciled with her actor dad Jon Voight although she has yet to decide whether he or her brother James Haven will give her away.
The couple's brood - Maddox, ten, Pax, eight, Zahara, seven, Shiloh, six, and twins Knox and Vivienne, three - will share some of the wedding day duties.
"The kids have been asking when they're going to get married for years.
Now they are pretty much the main reason Brad and Angelina are tying the knot," the source stated.
