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

Celeb Jeweler and CEO of, David Mamane tells "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.