Billie Eilish Celebrates Happier Than Ever Release with Family and Friends: 'She Had the Biggest Smile'

Matt Winkelmeyer/Getty Images for Spotify Billie Eilish

Billie Eilish celebrated her new album surrounded by her closest friends and family.

On Thursday night, Eilish, 19, counted down to the release of her new album Happier Than Ever surrounded by her mom, brother Finneas and her boyfriend Matthew Tyler Vorce at Spotify's Happier Than Ever: The Destination, an album release celebration at Beverly Hills mansion reminiscent of the 1950s.

Following a countdown to 9 p.m. PST, when the album was released, the singer jumped into the party's swimming pool fully clothed as she danced around with her close friends and boyfriend.

Matt Winkelmeyer/Getty Images for Spotify Billie Eilish

"When the album dropped, they were very sweet," the source says. "He was hanging out with her family. He seems very much a part of their life."

"She had the biggest smile on her face," the insider adds.

Matt Winkelmeyer/Getty Images for Spotify Willow and Jaden Smith

Matt Winkelmeyer/Getty Images for Spotify Ben Platt and Dove Cameron

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The event celebrated Spotify's new Enhanced Album feature and artist hub for Happier Than Ever with interactive experiences for attendees to enjoy the album in Billie Mode, Lyric Mode and Fan Mode. On the Spotify app, fans get to interact with several songs as they're brought to life with immersive experiences.

Among the attendees at Thursday night's event were Finneas, his girlfriend Claudia Sulewski, Khalid, Eric André, Olivia Rodrigo, Dove Cameron, Will.i.am, Ben Platt and Amanda Kloots, along with Willow and Jaden Smith.

Matt Winkelmeyer/Getty Images for Spotify Khalid and Will.i.am

Matt Winkelmeyer/Getty Images for Spotify Amanda Kloots

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July 30 also marked the birthday of Eilish's brother Finneas. From the swimming pool, Eilish invited partygoers to join her to sing "Happy Birthday" to her brother, who was all smiles as attendees celebrated him.

"Finneas and i were just on cloud 9 making this album i feel," she wrote on Instagram about the album. "I love every song on this project so so much it literally scares me thinking about putting it out into the world for anyone to listen to."

Michael Kovac/Getty Images for Spotify Claudia Sulewski and Finneas

matt winkelmeyer/Getty Billie EIlish

"I feel like crying," Eilish said.

Eilish and her boyfriend Vorce first sparked dating rumors in April when they were spotted in Santa Barbara taking a stroll with her dog Shark.

Happier Than Ever is out now.