The BBC has been playing its cards very close to the vest in the run-up to the new season of “Doctor Who,” which premieres Saturday on BBC America.

That’s not really anything new, since the British network understandably views the international cult hit as a flagship property, and it’s even more understandable in this case, since five scripts accidentally got leaked online just a matter of weeks ago. (The security lapse apparently happened when the scripts were sent to the BBC’s new Latin American headquarters in Miami for translation).

In any case, these new episodes are attracting special buzz not so much for their plot points, but because they feature a new incarnation of the Doctor, now played by Scottish actor Peter Capaldi. His character, a time-traveling space alien, is ancient in age, but periodically undergoes “regeneration” from one physical form to another.

It’s a neat conceptual hook that has allowed a series of actors to play the title role since the show originally premiered in 1963. Not counting John Hurt’s one-off appearance as a kind of “alt-Doctor” in last year’s 50th anniversary special, Capaldi is the 12th Doctor, but he’s only the fourth actor to essay the role in the current run of the series that was relaunched in 2005.

While “Doctor Who” has been revered by British fans for decades, the show really started to take off in the United States with the 10th Doctor, played by David Tennant, and his successor, played by Matt Smith, the youngest actor ever to tackle this iconic role.

In contrast, Capaldi is 56, and has built his career by playing intense characters like his comically profane Malcolm Tucker in the critically acclaimed political Britcom “The Thick of It.” Clearly he won’t be playing the Doctor in the boyish vein favored by Tennant and Smith.

In fact, Capaldi reveals in a recent interview with Empire magazine, fans can anticipate a Doctor who is a lot more “alien” than he previously has seemed. “He doesn’t really care much about human beings’ approval,” the actor added in that interview.