The couple started dating in 2005 and have six children together.
Pitt was previously married to actress Jennifer Aniston.
"Yes, it's confirmed," Pitt's manager Cynthia Pett-Dante told People.com Friday. "It is a promise for the future and their kids are very happy. There's no date set at this time."
Charlize Theron not engaged to Sean Penn 'yet'
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend