"For the last of the Time Lords, the clock is striking 12," said Steven Moffat, lead writer of the BBC hit "Doctor Who," just before the announcement that Peter Capaldi will become the 12 actor to play the iconic science fiction character once Matt Smith leaves the role this Christmas.

Capaldi, best known for playing foul-mouthed spin doctor Malcolm Tucker in BBC's political drama "The Thick of It," says he has already started to shed that previous persona and replace it with his version of The Doctor. At 55, he will be the oldest actor to take the role since the first Doctor, William Hartnell in 1963. He will be taking the helm of the TARDIS after Matt Smith, coincidentally the youngest actor to play the role at 26 when he was first introduced in 2009, departs.

The announcement was made at a live television event on BBC Sunday night, simulcast to BBC America the same day. Until that time, the Guardian reports that only ten people were aware Capaldi had been selected as the 12th Doctor.

"It is so wonderful not to keep this secret anymore," he said. "For a while I couldn't even tell my daughter. Being asked to play the Doctor is an amazing privilege. Like the Doctor himself I find myself in a state of utter terror and delight. I can't wait to get started."

The Glasgow-born actor has been a fan of the series ever since he was a child. Once confronted with a fan letter he wrote to the BBC when he was a boy, he admitted to playing the character in the schoolyard whe he was a child and downloading scripts and reading them in the mirror as an adult.

"I have not played him since I was nine," the actor joked.

Despite his nerves about playing the Doctor, Capaldi is no stranger to the Doctor Who universe. In 2008, during the 10th Doctor David Tennant's reign, he played Caecilius in an episode "The Fires of Pompeii." Fans might remember the episode for having the eleventh Doctor's companion, Karen Gillan, in it as well.

Capadi also played a key role as a higher up in the British government in the third series of "Torchwood," a spin-off show to Doctor Who where a team of alien-savvy scientists and soldiers combat extra terrestrial threats to Earth.

Matt Smith will exit the role during this year's Christmas special. After an unknown incident renders the eleventh Doctor on the verge of death, he will turn into a brand new man played by Capaldi.

Tell us what you think, are you pleased with the choice of an older Doctor? Comment and share your thoughts below.

(UPDATE: This article originally stated the actor practiced the character at nine in front of the mirror, not as an adult to research the series).