It has been announced by BBC that Matt Smith will leave the show after/during the Christmas Special. The announcement is already online, on sites such as Bleeding Cool and national newspapers such as Telegraph.
Matt Smith joined the show in January 2009 and has proven to be popular with the masses while some fans still find him too young and energetic. He replaced David Tennant to become the 11th Doctor. He will be appearing beside David Tennant in the Anniversary Special in November (as yet no title has been given) along with John Hurt who will also be The Doctor.
No replacement has been named as yet. Speculation is likely going to be rife. It isn’t the first time a Doctor Who has quit, won’t be the last. This is of course part of the beauty of the show. The central character can change enourmously when an actor leaves and yet the series can evolve.
It has been announced that his current assistant Clara, portrayed by Jenna-Louise Coleman, will be returning next year.
Confirmed on BBCs Doctor Who website