Chris Martin and rumored girlfriend Jennifer Lawrence, David Beckham, Adele, Adam Levine, Kendall Jenner, Courteney Cox, Rashida Jones, Cara Delevingne, and Kelly Osbourne were among the popular people attending the bash held at Lulu's Cafe in Beverly Hills.
Styles' rumoured girlfriend, Victoria's Secret model Nadine Leopold, reportedly was also in attendance.
While further details of the birthday bash remain unknown, it was reported that to mark Styles' 21st birthday, a One Direction fan named Amy Flanagan has raised more than USD 16,000 in a charity drive to benefit the London Lesbian and Gay Switchboard.