The Scots actor, 56, was sworn to confidentiality after agreeing to the role of the 12th Doctor earlier this year. But during the interim period before it was officially announced, Capaldi purposefully stood within touching distance of those fans desperate to know who the next Doctor would be.
He said: "When I was Doctor-elect, so to speak, I used to go to [sci-fi shop] Forbidden Planet and just hang around.
"It would amuse me that people wouldn't know they were standing next to the next Doctor. "
Before accepting the role, he admits to having one or two reservations.
He said: "I had to think about the level of visibility," he added. "People spoke to me before and recognised me, but nothing like this.
"I had to decide if I was ready to live with that."