The Serpentine Gallery Summer Party brought together some of the biggest stars in the business last night in London, where guests gathered for one of the highlights of the city’s social calendar. Alexa Chung (in Erdem), Keira Knightley (in Chanel), and Cara Delevigne (in Mulberry) were among the glamorous attendees (above) at the event, where Pharrell Williams gave a surprise performance. Bradley Cooper, Suki Waterhouse, Naomi Campbell, Orlando Bloom, Princess Beatrice, and Princess Eugenie, among others, also turned up at the soiree.

Held next to the Serpentine lake in the heart of the Royal Park of Kensington Gardens, the annual celebration unveiled a pavilion designed by Chilean architect Smiljan Radic—a fragile white fiberglass cocoon resting on top of a ring of boulders. The Serpentine Gallery and the newly opened Serpentine Sackler Gallery, designed by Zaha Hadid Architects, present world-renowned exhibitions of art, architecture, and design throughout the year, and throws the major bash each summer in honor of the featured works.

Check out all the stars who flocked to London for the Serpentine Summer Party in our gallery, plus more celebrities at this week’s hottest events!