The new showrunner told BBC Breakfast that a Cardiff screening of opener 'The Eleventh Hour' "went down a storm" and that viewers "seemed to absolutely love it".
Of the new Doctor, Moffat said: "What's Matt going to be like? He's going to be gorgeous, that's a fact... He's a sort of elegant shambles, is the best way to describe Matt. He's both clumsy and elegant at the same time."
Regarding concerns over the departure of David Tennant in the lead role, he added: "In a way you should be worried when The Doctor changes.
"It shouldn't be calm and easy for you, because this what puts the Who back in Doctor Who, the fact that he becomes a stranger again and you have to find him again and you have to get to know him again.
"I think really honestly and truly, in all my life as a Doctor Who fan, I like the new Doctor episodes best of all because it was kind of scary, because you didn't know him and yet you did."