David Tennant recently revealed his recent conversation that he had with the actor to take over his role as the Doctor, Matt Smith, to What's on TV magazine. You can read what David Tennant said to Matt Smith below;
"We chatted on the phone not long ago and we did exchange a few opinions on what’s about to unfold for him, but advice is a very dangerous thing. Matt’s got an extraordinary journey coming up in all sorts of ways and I’m sure he’ll find his own way through it."
"I could tell Matt was very up for it, though, and excited in all the right ways. He says he’s going to take it very seriously and he seems to have the right idea about playing The Doctor, so far as I can tell."
David Tennant will continue to play the Doctor in the remaining four Doctor Who specials that will broadcast throughout 2009 and 2010 before Matt Smith takes over as the 11th Doctor in Spring 2010.