Billie Eilish stood between her brother Finneas and Claudia Sulewski as they exchanged vows Saturday, taking on a considerably bigger wedding assignment than simply showing up for the family photos.
Eilish officiated the Aug. 29 outdoor ceremony at San Ysidro Ranch in Montecito, California, where Finneas and Sulewski married after nearly eight years together. Photos published by Page Six show the 24-year-old singer standing between the bride and groom as Finneas read his vows.
The couple’s rescue dogs, Peaches and Moose, had jobs of their own. They joined the celebration as “flower dogs,” wearing custom bows made from the same silk faille used for Sulewski’s wedding gown. Finneas and Eilish’s parents, Maggie Baird and Patrick O’Connell, were also there to watch their son get married.
The guest list included Justin and Hailey Bieber, Kristen Bell, Dax Shepard, Emma Chamberlain, Rachel Sennott, Rebecca Black and Jason Sudeikis. Sulewski turned the weekend into a fashion project of its own with four custom Oscar de la Renta looks, while Finneas wore a black suit and Eilish chose an off-the-shoulder green dress for her role at the altar.
Billie Eilish Officiated as Peaches and Moose Joined the Ceremony
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TMZ footage and photographs show her facing Finneas and Sulewski during the ceremony and confirm that Peaches and Moose were part of the celebration. The dogs’ participation had been planned down to their outfits. During Sulewski’s final fitting, Oscar de la Renta designer Grace McCoy revealed two silk faille bows cut from the same material as the ceremony gown. Sulewski explained that Moose would walk ahead of Peaches when the pair went down the aisle as flower dogs.
Eilish had already received an advance look at what her future sister-in-law would wear. During the fitting, Maggie Baird called her on FaceTime as Sulewski stood in the completed ceremony dress. “My God, I can’t believe it,” Eilish said when she appeared on the screen. “You look like an angel.”
Claudia Sulewski Had Four Custom Oscar de la Renta Looks
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Sulewski’s wedding wardrobe began before Saturday’s ceremony. Vogue documented her final fitting at Oscar de la Renta’s Beverly Hills boutique, where she tried on separate looks for the rehearsal dinner, ceremony, first dance and reception, and after-party.
For the ceremony, Sulewski wore an ivory silk faille ball gown with a drop-waist bodice and structured pleated skirt. An asymmetric draped scarf neckpiece extended down the length of the train, while a tulle veil was designed to fall from beneath her bun. The gown also had pockets, one of the details that drew particular approval during the fitting.
Her first-dance and reception dress was a structured cady gown with a sculptural peplum made from upcycled feathers and small crystal accents. Sulewski said the recycled feathers were especially important because her Cyklar beauty brand is vegan and cruelty-free. She had even tested dancing in the dress before the wedding, though Finneas had not been allowed to see it.
The after-party look changed direction again, a pink boat-neck top paired with a hand-draped dove-gray silk faille bubble skirt and matching heels. Sulewski said the design drew from Oscar de la Renta runway references from the 1990s and early 2000s.
Finneas Wrote ‘Claudia’ Almost as Soon as They Met
Finneas and Sulewski met through the dating app Raya in 2018, although she had already heard about him through mutual friends in the music business. Sulewski has said friends who worked with Finneas predicted the two would fall for each other before they ever matched.
Finneas apparently needed very little time to turn the new relationship into music. He has said he wrote “Claudia” the night they met and sent it to her that same night. Sulewski later directed and starred in the video for his 2022 song “Mona Lisa, Mona Lisa.”
The couple became engaged on Sept. 22, 2025, after Finneas took Sulewski by helicopter to a scenic mountaintop proposal. They announced the engagement two days later with photographs and video from the moment and the caption, “forever and ever 9.22.”