Celebrity pictures: Justin Bieber, Taylor Swift, Zac Efron

Today's celebrity pictures include Justin Bieber being mobbed by fans as he exits the Kiss FM studios in London, Made In Chelsea's Caggie attends the London premiere of The Lucky One and the film's star Zac Efron leaves the after-party at the Bluebird.

Meanwhile, Jesse Wood and Fearne Cotton leave the HMV Forum in Kentish Town, New Kids On The Block and Backstreet Boys perform in Liverpool, and in Hamburg, Joan Collins is the face of Snickers.

Across the pond in New York, Homeland star Claire Danes goes to the Hysteria screening at the Tribeca 2012 Film Festival, and Ethan Hawke and Bernie director Richard Linklater attend the black comedy's screening.

In Los Angeles, Hollywood couple Josh Hartnett and Amanda Seyfried pop out for coffee and a nautical-looking Taylor Swift goes shopping.