Kraft, who is the CEO of the Kraft Group and worth an estimated $8.3 billion, popped the question to leading New York City ophthalmologist Dana Blumberg with a '10-carat diamond', one source claims.
The couple, who have been dating for three years, had been keeping their news under wraps but Kraft's designer pal Tommy Hilfiger, 70
Tommy Hilfiger was the honoree and Robert and Dana were both chairs of the event for Tommy,' a source told Page Six.
[Hilfiger] said his "good friend Bob Kraft got engaged to Dr Dana Blumberg" at the event on stage, speaking to the whole audience.'
Another attendee noted Dr Blumberg was wearing 'a giant rock' at the gala that looked as though it was '10 carats or more', while comparing it to the enormous 'Super Bowl rings