Billie Eilish and Finneas O'Connell Are a Stylish Sister-Brother Duo at the 2023 Met Gala

Billie Eilish and Finneas O'Connell were a stylish sister-brother duo at Monday night's Met Gala. The pair arrived at the Metropolitan Museum of Art in New York City dressed to impress with their sleek looks in honor of this year's theme, which pays tribute to late fashion designer Karl Lagerfeld.

Eilish, 21, was draped in a sheer, high-neck black dress by Simone Rocha, complete with a corset, while her older brother, 25, wore a long brown leather trench coat with a teal button-up peeking out.

This isn't Eilish and O'Connell's first Met Gala together. The two were each other's red carpet dates last year when Eilish stunned in her pastel Gucci corset dress. The musical sibling duo have also frequented other big events together in the past, including the 2022 Grammy Awards, 2022 Oscars, and Coachella 2022 — all of which they performed at together — as well as the 2023 Vanity Fair Oscars afterparty.

Eilish also attended the latter event with her boyfriend, Jesse Rutherford, whom she went public with in November 2022 after she made their relationship Instagram official. Her subtle announcement came just after the pair were spotted kissing in NYC the month before.

Ahead, see more photos of Eilish and her brother's Met Gala night.