media_removed_toofab 102011

Angelina Jolie
has a sparkly new accessory on her left hand -- an engagement ring!

Brad Pitt's manager confirmed the news to The Associated Press on Friday, stating that while no wedding date has been set "at this time" the engagement is "a promise for the future."

Speculation over their engagement heated up after Angelina, Brad Pitt and son Pax were spotted looking at works from the Chinese collection at the Los Angeles County Museum of Art earlier this week ... where Angie had a BIG rock on her ring finger.

According to the Hollywood Reporter, the jeweler who designed the ring is Robert Procop -- and he's saying it was made in collaboration with Brad.

And yes, a rep for the jeweler specifically calls it an "engagement ring."

Procop isn't some random trying to get his name in the news either. He actually has a professional relationship with Angelina -- he also has a line of jewelry called "The Style of Jolie" that was designed with the star

Brad previously told the Reporter "We'd actually like to [marry] and it seems to mean more and more to our kids."

He added, "We made this declaration some time ago that we weren’t going to do it till everyone can. But I don’t think we’ll be able to hold out."

Brad and Angelina have six children, who Brad's rep confirmed are "very happy."