Doctor Who stars Matt Smith and Jenna-louise Coleman thrilled fans of the sci-fi show by making a special appearance at a convention in London on Friday (22Nov13) to kick off a weekend of 50th anniversary celebrations.

The outgoing Time Lord and his companion headed to London's ExCel centre to launch the 50th anniversary event, which runs until Sunday (24Nov13), and they met fans from all over the world who had travelled to the British capital for the convention.

Smith told reporters at the event, "We're very proud, it's a great privilege to be here. It's a great privileged to be the incumbent Time Lord... It's great fun and it's great fun for the fans."

Coleman adds, "We've got such an international crowd here... From Turkey, France, Brazil, Mexico, and meeting all these people who have travelled all this way just to be here for this weekend to say, 'Happy birthday', it's great."

Smith will bow out of the role in a special 50th anniversary episode of the popular show, which will air simultaneously in countries around the world on Saturday night (23Nov13), and he adds of his final appearance, "It's a celebration and we hope everyone is going to enjoy it."