The Beatles legend Sir Paul McCartney's representative confirmed the engagement on Friday, May 6, four days after the happy couple walked the red carpet at the annual MET Gala at New York's Metropolitan Museum of Art.
American heiress Nancy Shevell wasted no time in showing off her round-cut sparkler - she was snapped with her new piece of jewelery as she stepped out in the Big Apple shortly after the announcement.
An eyewitness tells Life & Style magazine, "Paul spent more than $650,000 on the gorgeous ring, and Nancy absolutely loves it!"
"You can tell she was excited to finally be showing it off. She was glowing and relaxed and looked like she couldn't be happier. She even gave a thumbs up when asked how her and Paul were doing. Clearly the couple is very happy."
The couple began dating in 2007, a year after McCartney split from second wife Heather Mills.