Credit: Kevin Mazur/

Kate Hudson's latest movie is entitled Something Borrowed -- but her brand-new engagement ring is definitely hers to keep!

The actress, 32, flashed her huge new bling during a Wednesday appearance on The Today Show; Matt Lauer was the very first to notice the sparkler.

A source close to the star tells Us Weekly that the bauble is approximately 9 carats, and that her beau, Muse rocker Matt Bellamy, proposed about a week ago in NYC.

"I'm engaged!" Hudson confessed to Lauer. "I haven't really announced it, I was waiting for someone to notice [the ring]."

Together since late spring 2010, Hudson and Bellamy, 32, are expecting their first child together in a couple months. The baby-to-be joins Ryder, her 7-year-old son with ex-hubsband Chris Robinson.