Peter Capaldi strikes a confident note as he takes on ‘Doctor Who’

Peter Capaldi has just landed in New York, the fifth stop in a worldwide tour promoting the new season of “Doctor Who” that began in the United Kingdom, continued with visits to South Korea and Australia and now, after a 22-hour flight that crossed the international dateline, has descended on midtown Manhattan. Next, he and costar Jenna Coleman head to Mexico and Brazil.

For Capaldi, who makes his proper debut as the 12th incarnation of the time-traveling, shape-shifting Doctor on Saturday, all the globe-trotting may be useful for getting into character. But, he says, “the TARDIS is a much more efficient vehicle for traveling,” referring of course to the Doctor’s famous blue police phone booth-cum-spaceship.

In Britain, “Doctor Who” has been part of the pop culture canon virtually since its premiere on the rather untimely date of Nov. 23, 1963. Stateside, the sci-fi series has long been a cult favorite. But since the dormant franchise was revived in 2005, “Doctor Who” has gradually edged out into the American mainstream, its popularity driven by the charismatic performances of David Tennant and Matt Smith as the 10th and 11th Doctors, and by the inventive writing of show runners Russell T. Davies and Steven Moffat. (Its availability on Netflix hasn’t hurt either.)

Last November, the 50th anniversary special “The Day of the Doctor” drew an audience of 2.4 million to BBC America, a record for the cable network. Globally, the show has a reach of more than 30 million viewers in 75 countries. Anticipation surrounding the new season is so intense that when footage and scripts were accidentally leaked online last month, the BBC issued a public plea for fans to keep spoilers to themselves.

Capaldi is sanguine about the intense scrutiny he’s under given that he’s taking on the role after a string of popular younger actors, and Whovians are known for their intense devotion to particular incarnations of the Doctor.

“One of the nice things about ‘Doctor Who,’ and I know from being a fan myself, is even if a lot of people don’t like me, some people will love me,” says the 56-year-old Scot, dressed stylishly in a slim-cut blue suit and wingtip Doc Martens, “that somewhere there will be a little group of people that says, ‘Oh, that’s my Doctor,’ and the more everybody else hates me the more they’ll love me.”

For Moffat, who has worked on the series since its reboot and took over the reins as show runner from Davies in 2010, Smith’s departure after three seasons was a tough blow. “At a simple human level, it was miserable because my mate went. And also it’s a strange thing, because we did make a radical change to the Doctor, that light goes out and the 11th Doctor is not there anymore. That lovely, floppy man is gone.”

Given that one of the Doctor’s essential traits is his mutability, one might think that casting would be a daunting process: Where does one begin narrowing down the list of candidates when there are no real limitations in terms of age or appearance?

“They’ve got to be technical virtuosos,” Moffat says. “You need somebody you’ll never tire of listening to and never tire of looking at. You have to picture them on a fridge magnet, you have to picture them on a lunch box.”

Yet what might have been a long and difficult quest for a new Doctor was “over in a heartbeat,” Moffat says, because he immediately thought of Capaldi and “everyone mysteriously agreed.”

Unlike Smith, who was a relative unknown before “Doctor Who,” Capaldi is already a beloved and highly recognizable star in the U.K., thanks to his portrayal of Malcolm Tucker, the prime minister’s ruthless and blisteringly profane enforcer in Armando Iannucci’s political satire “The Thick of It.” (A role he reprised in the film adaptation, “In the Loop.”)

Despite Capaldi’s strong identification with a very particular (and decidedly unheroic) character, Moffat saw little downside in casting the actor, whom he calls “a national treasure.” (His evidence? At the BAFTAs a few years ago, cheers for Capaldi were as deafening as they were for “Sherlock” heartthrob Benedict Cumberbatch.)

Capaldi had closely followed all the casting speculation in the press and says he was “slightly peeved that no one was mentioning me at all” when his agent called to ask how he’d feel about being the new Doctor. After reading for Moffat — he was the only actor to do so — Capaldi got the part, despite what he describes as a “truly awful” audition.

For Capaldi, who grew up admiring Vincent Price and Peter Cushing, stars of the horror and sci-fi films he loved, rather than Shakespearean types like Richard Burton or Laurence Olivier — he says their names with an affected posh accent — playing the Doctor is “part of my DNA.”

Though he had to keep the secret to himself for a very long 2 1/2 months, Capaldi quietly found ways to celebrate. He’d often visit Forbidden Planet, a comic book and sci-fi emporium in London. “I’d wander in there and stand sort of close to people thinking, ‘They don’t know that Doctor Who’s standing next to them, and if they did know, they’d be very excited.’ I hope that maybe they’ll read this and in their memory they’ll go, ‘There was a strange guy standing next to me…’

“Toward the end it became a bit difficult because you’re actually just lying to people,” says Capaldi, who dodged other job offers by making vague references to nonexistent sitcoms. “I had my own personal pilot season.”

Though Capaldi is not the first Scottish actor to portray the Doctor, he is the first to speak in his native accent, a decision he made out of a desire to “remove excess baggage” from the part. (This pared-down philosophy also seems to have extended to his sartorial choices, with the new Doctor adopting a minimalist, tie-free look.)

The actor promises that the new season, which finds the Doctor and his companion Clara (Coleman) landing in Victorian London, is “scarier and darker” than it’s been in a few years. Accordingly, there may even be a hint of Malcolm Tucker in Capaldi’s crankier, less socially adept Doctor, who will be seen getting “impatient, vexed, worried” about his valiant image this season, according to Moffat.

“Whereas Matt’s doctor and David’s doctor were charmier, Peter’s Doctor doesn’t really bother,” explains the writer. “The Doctor is aware that some people regard him as a hero and legendary warrior, but he knows he’s just a bloke in a time machine bluffing his way from one adventure to the next.”

The Doctor’s regeneration proves particularly challenging to Clara. “You try to think about it in a truthful way: OK, what would I do if my best friend in the world changed his face and personality?” says Coleman, who actually learned of Capaldi’s casting under very different circumstances, during a visit by Prince Charles and Camilla, the Duchess of Cornwall, to the “Doctor Who” set.

“It was quite a surreal day,” she recalls.

In contrast to the quasi-romantic relationship between Clara and Smith’s Doctor, this time around romance is decidedly off the table, says Coleman. “He literally barely registers the fact that she’s a girl.”

Twitter: @MeredithBlake