Similar to when the pair were spotted in August at the Paddle and Party for Pink fundraiser, Mary-Kate made sure to keep her engagement ring tucked away between herself and her older beau.
The ring, which was first spotted during Paris Fashion Week, is an intricate Cartier piece dating from 1953 — a fitting choice considering the blonde beauty's penchant for vintage clothing. It features a four-carat central diamond flanked by 16 sapphires, and the "petals" are set with single-cut diamonds.
Mary-Kate and fiancé Oliiver Sarkozy take in the action at the US Open
"I'm, like, not even there yet," she said. "I think it may be a matter of getting five or six, or making two or three and being stressed out. That seems kind of far away. We'll take one step at a time."
Younger sister Elizabeth, who is engaged to Boyd Holbrook, also recently spoke about her own wedding plans, and when asked about whether she had picked a wedding date and whether it would coincide with her big sister Mary-Kate, said, "No, I just told her she gets to pick a date first!"