Is there going to be another Doctor on Doctor Who?

Answer 1

Yes. A new actor will be introduced as the new Doctor after Matt Smith leaves in the 2013 Christmas special.

A Time Lord is, according to the show, able to regenerate thirteen times. We're currently on the eleventh regeneration (played by Matt Smith), so, yes, eventually we will have at least two more Doctors.

There is some debate about whether or not they will continue the show after the thirteenth Doctor's death; there's a possibility that the writers will go against the history of the show and find a way for him to regenerate again, or maybe they'll just pass on the Doctor's legacy to a son we don't know about or a worthy companion.

It should be noted that in the series itself it has been strongly indicated since at least 1983 that 13 is not a hard and fast rule. In The Five Doctors and the 2007 episode The Sound of Drums it was indicated that the High Council of Time Lords had the ability to reset the regeneration cycle, as this was offered (and later given) to the Master. The Master also used various methods to gain more lives after his original 13. More recently, Russell T Davies, Steven Moffat and David Tennant have all downplayed the significance of the 13, and it is assumed it will simply be ignored when the time comes; for those who feel canon must be adhered to, the above reference to the High Council controlling regenerations provides the out: they no longer exist, therefore the 13-life cap no longer exists. In the Sarah Jane Adventures story "Death of the Doctor", the Doctor says he can regenerate 507 times. This was intended as a joke, according to Davies, but could end up being more the case down the line. One thing for sure - if Doctor Who remains as popular as it is now in 5-10 years when the actor or actress playing the 13th Doctor decides to leave the series, there is no way the series will end. They'll either ignore the limit completely, or "hand wave" it away. The introduction of a previously unknown incarnation of the Doctor in "The Name of the Doctor" - which could render the Doctor who follows Matt Smith at the end of the 2013 Christmas special as the 13th Doctor - has also increased the likelihood that a workaround will be used to avoid the limit. As of 2013, Doctor Who remains BBC Worldwide's top moneymaking series; they will not end it anytime soon.

Answer 2

Yes, new actors are periodically cast in the role of The Doctor in the television series Doctor Who. When the current Doctor departs, another actor will be chosen to take on the role.