Mary-Kate Olsen & Olivier Sarkozy: First Post Engagement Appearance!

Mary-Kate Olsen cozies up to her fiance Olivier Sarkozy while attending the book launch party for Bob Colacello‘s “Holy Terror: Andy Warhol Close Up” at the Diane Von Furstenberg Studio on Monday evening (March 10) in New York City.

The 27-year-old fashion designer showed off her massive engagement ring while leaning on the signing table to chat with Bob while he autographed her book.

PHOTOS: Check out the latest pics of Mary-Kate Olsen

Mary-Kate is back from Paris, where she was last week with her twin sister Ashley to attend some events during fashion week.