During David Tennant's interview with the current issue of TV & Satellite Week he spoke briefly about his return to Doctor Who for the 50th Anniversary Special.
"It is strange being back in the same suit, but it also feels very familiar and comfortable. There's nothing quite like Doctor Who. It has a wonderful excitement about it. I always had happy times there and it's lovely to be around Billie again, even though I see her all the time anyway."
Read the full interview here.