Billie Eilish officiates her brother Finneas’s wedding in Montecito

Billie Eilish was not just a guest at her brother Finneas O’Connell’s wedding to Claudia Sulewski. The 24-year-old singer officiated their ceremony on August 29 in Montecito, California, after the couple reached a very personal compromise while planning their nuptials.

Claudia Sulewski explained in a video posted on September 9 on YouTube that Finneas initially wanted his sister to be his best man, while she wanted him to stand by her side as a maid of honor. Ultimately, the couple decided to give her a unique role: that of marrying them. The content creator described this presence as one of the most beautiful gifts they received for their union.

The ceremony took place outdoors in a deliberately intimate atmosphere. According to Vogue, the couple chose not to have a bridal party or groomsmen, preferring to focus the celebration on their loved ones. Billie Eilish found herself at the center of a moment that was both familial and highly symbolic for her brother, with whom she has shared a close musical collaboration for years.

The singer also participated in the reception, where she performed Birds of a Feather, one of her biggest hits, in front of the guests. Justin and Hailey Bieber, Kristen Bell, Dax Shepard, Jason Sudeikis, Nina Dobrev, Emma Chamberlain, and several other celebrities were among the announced guests surrounding the newlyweds.

Billie Eilish had already been involved in the preparations a few days before the ceremony. During Claudia Sulewski’s final fitting at Oscar de la Renta, she discovered the wedding dress via video call and praised the future bride’s choice. Claudia Sulewski wore several creations from the American house during the wedding weekend, while Finneas opted for a Prada outfit.

Finneas O’Connell and Claudia Sulewski met in 2018 on the Raya app. Their relationship continued for seven years before their engagement, announced in September 2025. The musician and producer proposed to his partner during a getaway in the Santa Monica mountains.

After the ceremony, Claudia Sulewski shared that she was still very emotional about the memories of that day. She explained that certain songs played during the wedding were still enough to make her cry nearly two weeks after exchanging vows with Finneas.