Fashionista Olivia kicked off her New Year in style by accepting a proposal from hunky Johannes while holidaying in St Barts.
They announced their happy news via a (slightly cheesy?) Instagram video on New Year's Day, which was posted by Johannes with the caption: "Happy New Year to everybody and this is how we celebrate it: OP said Y E S."
In the video, Olivia is seen running across the beach, every so often glancing back coyly at the camera. Then, she flashes her engagement ring - and a smile.
Olivia and Johannes marked the New Year in the Caribbean.
They have been together since 2008.
Olivia's engagement comes a month after her former The City co-star Whitney Port announced her engagement to boyfriend Tim Rosenman.