Justin Bieber was the first star to defy the 'no selfies' rule at the Met Gala.

Guests at the New York event - held at the Metropolitan Museum of Art last night (04.05.15) - were warned against taking photos by Vogue magazine's US editor, Anna Wintour, although the 'Boyfriend' singer was quick to break the rule, posing for a snap with supermodel Cara Delevingne shortly after arriving.

According to the New York Post newspaper's Page Six column, the editor's note prior to the ball read: ''The use of phones for photography and social media will not be permitted inside the gala.''

However, the 21-year-old singer wasn't the only star to break the regulations for the 'China: Through the Looking Glass'-themed event, as a host of other celebrities also shared snaps across their social media profiles.

Kim Kardashian West - who attended the ball in a sheer Roberto Cavalli gown - posted several snaps to her Instagram account throughout the evening as she posed with famous faces such as her husband Kanye West, as well as Madonna, Lady GaGa, Cher, Marc Jacobs and Jennifer Lopez, who she described as her ''idol''.

Madonna also threw caution to the wind by sharing a variety of photos with her 3.7 million Instagram followers, including one with fellow female singers Katy Perry and Lady Gaga.

Captioning the picture, she wrote: ''Girls night out.......... Kissing the Ring........Finally!#metball (sic).''

Reposting the shot on her own account, Katy Perry joked: ''dropping our single tomorrow #stolethispicfromM#MONSTERCATREBELHEARTS (sic).''