Ben Affleck Snaps Up New 'Massively Protected' L.A. Crib Away From Paparazzi

Ben Affleck is ready to bid his Brentwood mansion goodbye ... and move into a "super high-end" and "massively private" crib, TMZ has learned.

Sources tell us ... Ben had been eyeing the new property for a while -- and it seems he pulled the trigger and bought it last year.

There is a slight snag of sorts -- the new pad is still under construction, but as soon as it's ready, Ben will bounce from his current Brentwood digs.

From what we hear ... this new place is something of a Fortress of Solitude .... meaning it's impossible to see from the street, giving Ben a lot more peace than he has at his current place, where he is constantly snapped by paparazzi.

We broke the news that Jennifer Lopez was recently looking at a place in Brentwood she really liked ... but her hunt has nothing to do with Ben's decision. The actor has been saying for a while now he was ready for a new place.

As for the swanky L.A. mansion Ben and J Lo once called home -- it's still up for grabs, sitting on the market with a hefty $61 million price tag.