He was cast over Christmas and will begin filming for the fifth series of Doctor Who in the summer. Tennant is filming four specials in 2009.
Smith was named as Tennant’s replacement in Saturday’s edition of Doctor Who Confidential on BBC One.
He said: "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."
Thanks to Misty at Shakesville for feeding me this information! Now my appetite is whetted I am even more keen to see it all come together. And that is the understatement of 2009. Already.