Jennifer Aniston Engagement Ring Revealed (Photo)

Jason Thomas/FilmMagic

Nearly two months after Jennifer Aniston said "yes" to Justin Theroux, the actress has finally revealed her rock.

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Aniston played coy with photographers in mid-August, stepping out on the set of We Are the Millers with a conveniently placed white towel over her left hand, shielding the sparkler from long-lensed photogs. But on Saturday in Santa Fe, on the set of her new film, Aniston put her ring on display while sharing a moment with her groom-to-be.

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With the poor quality of the photo, it's difficult to pinpoint exact details of the bauble, but Forevermark Diamond expert Adelaide Polk-Bauman tells The Hollywood Reporter that Aniston's diamond looks to be approximately 12 to 14 carats. As for the diamond cut, that could be anywhere from an oval, to oval cushion or an emerald cut.

"Given the potential cut and carat weight of this diamond, it is probably high color and clarity grade with little to no inclusions," says Polk-Bauman, who estimates the ring's value at over $1 million.

No word yet on who designed the stunning sparkler.

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The couple met on the set of Wanderlust in 2011 and had been dating for just over a year when Theroux popped the question on Aug. 10. In a statement to the media, Theroux's rep said, "Justin Theroux had an amazing birthday on Friday, receiving an extraordinary gift when his girlfriend, Jennifer Aniston, accepted his proposal of marriage."

This will be the first wedding for Theroux, who was previously in a longtime relationship with costume designer Heidi Bivens, and the second for Aniston, who wed Brad Pitt in 2000.

Additional reporting by Carol McColgin.