Matt Smith was today named as the new Doctor Who, the BBC said, becoming the 11th Time Lord since the programme first aired in 1963.
Mr Smith will replace David Tennant at the helm of the Tardis, and is due to first appear on our screens as the revered doctor in 2010.
Smith, 26, is the youngest ever doctor and although relatively unknown, has appeared in Alan Bennett's play The History Boys at the National Theatre in London, and alongside Christian Slater in Swimming with Sharks in the West End.
He said he was delighted to take on the role.
He explained: "I've got this wonderful journey in front of me. I've got six months to build this Time Lord and that's such an exciting prospect."
Smith was unveiled live on BBC1 and with the broadcast beamed live on BBC big screens nationwide.
He added: "I'm just so excited about the journey that is in front of me. It's a wonderful privilege and challenge that I hope I will thrive on.
"I feel proud and honoured to have been given this opportunity to join a team of people that has worked so tirelessly to make the show so thrilling.
"David Tennant has made the role his own, brilliantly, with grace, talent and persistent dedication. I hope to learn from the standards set by him.
"The challenge for me is to do justice to the show's illustrious past, my predecessors, and most importantly, to those who watch it. I really cannot wait."
Tennant announced in October last year that he would be stepping down from his role as the doctor at the end of this year.
The fifth series of the much-loved sci-fi hit will also have a new lead writer and executive producer with Bafta award-winning writer Steven Moffat taking over from Russell T Davies.
Moffat will be joined by Piers Wenger, who will be the new executive producer for BBC Wales making the show.
Wenger, head of drama at BBC Wales, added: "With two hearts, a ferocious mind and over 900 years of experience behind him, it's not every 26-year-old actor who can take on a role like the Doctor but within moments of meeting Matt he showed the skill and imagination needed to create a Doctor all of his own.
"It's just the beginning of the journey for Matt but with Steven Moffat's scripts and the expertise of the production team in Cardiff behind him, there is no-one more perfect than him to be taking the Tardis to exciting new futures when the series returns in 2010."
Four Doctor Who specials featuring Tennant will run in 2009 into New Year 2010 before Smith appears on our screens.
Tennant told the Doctor Who Confidential programme: "It's funny really, as I begin the end of my connection to all of this I do feel a bit of jealousy of Matt who's kind of just about to start and has got all off this ahead of him and it's a very exciting journey to go on."
The identity of the new Doctor has been strictly guarded by the BBC.
Favourites for the role had changed seemingly week-in week-out as more and more actors' names were put forward by the media.
David Morrissey, Catherine Zeta Jones, Martin Clunes and even David Walliams were amongst others mooted for the part.
But Smith finally won the prized role and said he was still in a state of shock following his appointment.
He explained: "I'm flabbergasted, I haven't slept really to be honest."
He added: "It's an iconic part of our culture, my grandad knows about it, my dad knows about it, it's been going since 1963 it has the iconic status of Robin Hood or Sherlock Holmes."
Moffat who helped chose the new Doctor said he knew Smith was perfect to fill Tennant's boots as soon as he saw him.
He explained: "The Doctor is a very special part, and it takes a very special actor to play him. You need to be old and young at the same time, a boffin and an action hero, a cheeky schoolboy and the wise old man of the universe.
"As soon as Matt walked through the door, and blew us away with a bold and brand new take on the Time Lord, we knew we had our man."