Big screen funnyman Jim Carrey has turned on the Christmas lights at London's Oxford Street.

The Hollywood actor was joined in the capital by Colin Firth, fellow star of Disney's new animated film A Christmas Carol, who illuminated nearby Regent Street.

Bob Hoskins, who voices Mr Fezziwig and a pawnbroker in the film, did the honours at St Paul's Cathedral.

There was musical entertainment from acts including girl group The Saturdays, Peter Andre, Spandau Ballet and The Noisettes in the build up to the switch-ons.

It is the 50th anniversary of the Christmas lights on Oxford Street and the first time the illuminations have been turned on at the same time as those on Regent Street.

After the switches were flicked, award-winning singer Andrea Bocelli and the St Paul's Cathedral Choir led crowds in an attempt to stage the world's biggest carol singing event.

A bearded Carrey said the singing was "beautiful". He called A Christmas Carol "the best version that's ever been seen" and added: "It's a new era and a new way of seeing this story."

Carrey, 47, who voices characters including Scrooge in the animated film, explained how he prepared for the role.

"The belief that he has through his entire life that he is unloved and unworthy of love, that's where I started," he said. "That creates a spiritual acid reflux as it were."

The Christmas light events were followed by the premiere of A Christmas Carol in three cinemas in Leicester Square as well as 10 others around the country.