Jennifer Aniston is gonna have to come up with something pretty special if she plans on upstaging her 'nemesis' Angelina Jolie at the Oscars, if the latest reports are on the money.

Brad Pitt's current leading lady – who is nominated in the Best Actress category for her role in Changeling – is reportedly keen to ensure that all eyes are on her during the most glittering night of the Hollywood calendar.

And what better way to do that than by out-blinging her actress rivals – including Jen - on the red carpet?

"She's been driving all of the high-end jewelers of New York crazy," a source tells OK!.

"She's looking for the impossible - a drop dead gorgeous $20 million diamond necklace to wear to the Oscars.

"She really wants it to be a show-stopper and is making sure that she is the one everyone has their eyes on this Sunday - and not Jennifer Aniston."

Angelina and Jennifer are expected to cross paths at this weekend's ceremony, their first meeting since Angelina "fell in love" with Brad while he was still married to the former Friends actress.