Beautiful! The girl AND the ring :)

Katherine Schwarzenegger flashed her gorgeous cushion-cut diamond engagement ring from fiance Chris PrattM as she hit the grocery store in Brentwood, on Tuesday.

The 29-year-old daughter of Arnold Schwarzenegger and Maria Shriver -- author of I Just Graduated, Now What? and Rock What You've Got -- wore a casual, all-black look, topped off with a cozy sherpa jacket for an outing to the supermarket. And of course she carried hemp recyclable bags!

Mom Maria was on The Today Show Tuesday morning and was, of course, asked about her daughter's engagement to which she replied that she's not allowed to talk about it because "it's not my moment!" Still, we have a feeling this cute couple's going to become everybody's moment because fans just can't get enough of them! Wedding watchers, stay tuned!