The couple got engaged in April and are planning a late September wedding.
Pitt has managed to buy a luxurious Patek Philippe Minute Repeater despite the that fact that there is usually a two-year wait for the piece.
Each piece is checked by a member of the Stern family who own Patek Philippe at the firm’s headquarter in Geneva.
“Brad decided to buy one of the amazing watches after meeting the Stern family at a watch fair in Basel,” thesun.co.uk quoted a source as saying.
“He wanted to buy Ange a unique gift that very few people own which is like a piece of art – and the highly sophisticated watch is just that,” the source added.
The time piece takes two months to make and has a pearl dial and is gold.
“He (Pitt) went to Geneva to pick it up and it’s believed he’ll present it to Ange as a pre-wedding gift,” the source said.