The Thick of It actor was announced as the replacement for Matt Smith in August (13) and is gearing up to make his first appearance in the long-running sci-fi show later this month (Dec13).
Capaldi's unveiling on a U.K. Tv special ended months of speculation over who would land the coveted role, but the show's executive producer Steven Moffat now reveals there was only ever one man in the running.
He says, "We asked and he was incredibly excited to come and audition. We didn't tell him that he was the only person auditioning because that would be oddly pressuring.
"He's one of the best actors in the country and is very beloved. I was at the BAFTAs (awards), shortly before we were contemplating Peter, and heard the cheer he got from the audience.
"Nobody has a bad thing to say about him and that's not a minor issue when it comes to casting a Doctor. They've got to be lovely. And he's a huge fan of Doctor Who."