Actors Matt Smith (R), who plays “Doctor Who”, and Jenna Coleman, who plays “Clara Oswald”, in the science fiction series “Doctor Who” pose for a photograph with Steven Moffat (L), the series writer, at the “Doctor Who 50th Celebration” event in the ExCeL centre on November 22, 2013 in London, England. The sold-out three day event in the ExCeL London convention centre celebrates 50 years of the show which has seen 11 actors play the role of Doctor Who and receives a worldwide cult following. (Photo by Oli Scarff/Getty Images)

Doctor Who fans pose for a photograph in front of a model of the TARDIS at the “Doctor Who 50th Celebration” event in the ExCeL centre on November 22, 2013 in London, England. (Photo by Oli Scarff/Getty Images)

Visitors admire an actor in costume at the “Doctor Who 50th Celebration” event in the ExCeL centre on November 22, 2013 in London, England. The sold-out three day event in the ExCeL London convention centre celebrates 50 years of the show which has seen 11 actors play the role of Doctor Who and receives a worldwide cult following. (Photo by Oli Scarff/Getty Images)

A Doctor Who fan drives a mobility scooter decorated to resemble a Dalek at the “Doctor Who 50th Celebration” event in the ExCeL centre on November 22, 2013 in London, England. (Photo by Oli Scarff/Getty Images)

Doctor Who fans meet an actor dressed as a “Cyberman” at the “Doctor Who 50th Celebration” event in the ExCeL centre on November 22, 2013 in London, England. (Photo by Oli Scarff/Getty Images)

A security guard walks past a giant Doctor Who poster at the “Doctor Who 50th Celebration” event in the ExCeL centre on November 22, 2013 in London, England. The sold-out three day event in the ExCeL London convention centre celebrates 50 years of the show which has seen 11 actors play the role of Doctor Who and receives a worldwide cult following. (Photo by Oli Scarff/Getty Images)

Billy Arratoon, 16, from Crawley dresses as his favorite Doctor during a visit to the Doctor Who Official 50th Celebration at the London Excel Centre Docklands, on November 22, 2013. (Photo by Chris Radburn/PA Wire)

A Doctor Who fan takes a “selfie” photograph on her mobile phone with a Dalek at the 'Doctor Who 50th Celebration' event in the ExCeL centre on November 22, 2013 in London, England. The sold-out three day event in the ExCeL London convention centre celebrates 50 years of the show which has seen 11 actors play the role of Doctor Who and receives a worldwide cult following. (Photo by Oli Scarff/Getty Images)

A character from Doctor Who entertains the crowds during the Doctor Who Official 50th Celebration at the London Excel Centre Docklands, on November 22, 2013. (Photo by Chris Radburn/PA Wire)

A person dressed as a Cyberman from Doctor Who strolls along during a visit to the Doctor Who Official 50th Celebration at the London Excel Centre Docklands, on November 22, 2013. (Photo by Chris Radburn/PA Wire)

Wendy Taylor from Harwich, Essex, dresses as a Dalek cduring a visit to the Doctor Who Official 50th Celebration at the London Excel Centre Docklands, on November 22, 2013. (Photo by Chris Radburn/PA Wire)