Credit: INFphoto.com

Over the weekend, Simon Cowell's fiancee, Mezhgan Hussainy, showed off her stunning engagement ring.

Celeb Jeweler and CEO of MyJewelryBox.com, David Mamane tells UsMagazine.com: "I never would have pegged Simon Cowell to be a guy that spends so much money on a woman. But he sure did well! The brilliant cut diamond engagement ring is approximately six carats and an estimated $750,000. You can see that the clarity and color is nothing less than perfect!"

On Friday, a source close to Cowell, 50, confirmed to Us that he had popped the question. Hussainy, 36, also announced the news to RadarOnline.