Credit: REUTERS/Mario Anzuoni

Diamonds may be a girl's best friend, but it seems Brad Pitt is awfully fond of them as well.

Angelina Jolie, 35, commissioned London-based jewelery designer Robert Procop to create a diamond pendant for her beau, 47, engraved with a love message a source confirms to

The actress has donned Procop's designs on several red carpets and is even working with him to create her own jewelry line, The Style of Jolie.

The pair based the pendant -- which is worth a six-figure sum -- on Ancient Egyptian amulets that contained hidden messages.

As for the engraved missive, "The hidden message is lasered on," Procop told UK's Daily Mail. "I can't tell you what it says, and you would need a microscope to read it!"