Mary-Kate Olsen makes rare public appearance at Moda Operandi's NYFW party

We don't often see Mary-Kate Olsen, but when we do, we know she'll still be nailing that ultra-cool NYC-but-boho aesthetic.

The 33-year-old fashion designer, whose label The Row will showcase its spring 2020 collection on the runway during New York Fashion Week, made an appearance at Moda Operandi's NYFW party on Thursday. Twin Ashley was absent from the event.

Looking demure in a black long-sleeved number, Mary-Kate posed for a photo with Sara Moonves, who is the Editor-in-Chief of W Magazine (and the daughter of ousted CBS CEO Les Moonves).

Moda Operandi co-founder Lauren Santo Domingo hosted the ultra-exclusive event at her home, greeting famous faces including Sienna Miller, Poppy Delevingne and Tory Burch. Guests toasted Moda Operandi's just-debuted rebranded design.

The Olsen twins are considered two of the most elusive socialites of the New York City scene. Although they make occasional annual appearances, like at the Met Gala and the CFDA Fashion Awards, they largely stay under the radar.

Mary-Kate has said that she's kept busy as a stepmom to two children. Her husband is 50-year-old Olivier Sarkozy, the brother of former French president Nicolas Sarkozy.