Angelina Jolie and Brad Pitt are engaged to marry, a spokeswoman for Pitt said on Friday.
"Yes, it's confirmed. It is a promise for the future and their kids are very happy. There's no date set at this time," Pitt's spokeswoman Cynthia Pett-Dante told Reuters.
Pitt, 48, and Jolie, 36, have been a couple since 2005, and are raising six children together, but until now have said they had no plans to marry.
But Jolie was photographed at a Los Angeles museum this week wearing a large diamond ring on her engagement finger that Pitt had helped to design.
Jewelry maker Robert Procop said he had fashioned the ring in collaboration with Pitt, specifically for the actress.
"The full creative journey - from conception to completion - took a year, with Brad Pitt waiting until the perfect moment to unveil this special jewel to Angelina Jolie," Procop's spokeswoman said in a statement on Friday.
The couple, dubbed Brangelina by celebrity media, have previously resisted pressure to marry, despite numerous reports over the years that a wedding was in the offing.
Pitt, the star of Moneyball, said some years ago they would not wed until gay marriage was legalized in the United States.
But in January he was quoted as saying that the pair were coming under pressure from their three adopted and three biological children.
"It (marriage) seems to mean more and more to our kids. We made this declaration some time ago that we weren't going to do it 'til everyone can. But I don't think we'll be able to hold out," Pitt told The Hollywood Reporter in an interview.
"It means so much to my kids, and they ask a lot. And it means something to me, too, to make that kind of commitment ... But to be in love with someone and be raising a family with someone and want to make that commitment and not be able to it is ludicrous, just ludicrous," he added.
Pitt and Jolie became close on the set of the movie Mr. & Mrs. Smith. Pitt later divorced Friends actor Jennifer Aniston.
Jolie, who won a best supporting actor Oscar for her work on Girl, Interrupted in 1999, had two previous short-lived marriages to actors Billy Bob Thornton and Jonny Lee Miller.