Yep during the 2013 Christmas Special he will regenerate into the 12th Doctor - the actor has yet to be named.
http://www.bbc.co.uk/news/entertainment-arts-22741493
This could be interesting as the current storyline has John Hurt playing some-part of the Doctor - either the very 1st Doctor, which would make Matt Smith's Doctor actually being number 12 and not number 11 or he could be The Valeyard (aka 13th Doctor but encompassing all that is bad of the Doctor)
Also according to Doctor Who folklore Timelords can only have 13 lives - but this was changed during an episode of Sarah Jane Smiths Investigates when the Doctor claimed that Timelords can regenerate as many times as they want!!!
http://www.bbc.co.uk/news/entertainment-arts-22741493
This could be interesting as the current storyline has John Hurt playing some-part of the Doctor - either the very 1st Doctor, which would make Matt Smith's Doctor actually being number 12 and not number 11 or he could be The Valeyard (aka 13th Doctor but encompassing all that is bad of the Doctor)
Also according to Doctor Who folklore Timelords can only have 13 lives - but this was changed during an episode of Sarah Jane Smiths Investigates when the Doctor claimed that Timelords can regenerate as many times as they want!!!