Peter Capaldi And Pearl Mackie On Why The New ‘Doctor Who’ Companion Should ‘Challenge’ The Time Lord

Pearl Mackie is having fun. When BBC affiliates announced the then-28-year-old actress as the new Doctor Who companion in April, they accompanied the fanfare with a two-minute scene featuring her, Peter Capaldi’s Twelfth Doctor and a bunch of Daleks. In the clip, the pair race through the halls of an unknown ship, avoiding capture and death while Mackie’s character, Bill questions the Time Lord incessantly about his iconic enemies.

“What’s a Dalek?” Realizing he’s dealing with a new companion, the Doctor grows impatient and says, “Never mind. It’s a Dalek.” Frustrated, Bill criticizes his non-answer and repeats the question. “Well that’s not explaining! That’s just saying a word. What’s a Dalek?” What the Doctor describes as a “tank” subsequently confronts them, but all Bill can do is poke fun at its “suckers” and annoy her host with more questions.

Doctor Who has lacked this kind of pervasive, meta-humor in recent years, and it’s evident from his onscreen interactions with Mackie that Capaldi is loving every minute of it. The same can be said for the now-29-year-old performer after we chatted with her, Capaldi, showrunner Steven Moffat and executive producer Brian Minchin at the 2016 New York Comic Con in October. A stage actress whose recent foray into films and television include the Martin Freeman-starring Svengali and the medical soap opera Doctors, Mackie didn’t yet know what to make of the convention. But when it came to discussing her new role, she knew precisely what she was doing.

“She’s a bit of a challenge,” says Mackie. “I think that’s why he likes her, because she doesn’t necessarily react in the way he expects her to. She’s not predictable and very sharp, and he’s interested in the way she reacts to new information. That’s one of the first draws between them. However, she’s obviously fascinated by him and the way his mind works, as she’s never met anyone quite like him.”

Capaldi couldn’t agree more, saying what interested him most about Bill was that she came “from a perspective we haven’t seen for awhile.” Basically, the new companion “has nothing whatsoever to do with the Doctor Who universe. Everything in the show is brand new to her. I think that’s very invigorating for us, as it means we have to retell — or tell afresh — the whole story. We have to explain what all the bits and pieces are. Bill never quite reacts to it in the way the Doctor expects her to.”

The 58-year-old star of The Thick of It, Armando Iannucci’s British predecessor to Veep, was especially drawn to the opportunity both Mackie and the Bill character presented. Mainly, that Mackie and Bill’s arrival would let Capaldi breath new life into his third season as the Doctor while contending with their outsider’s perspective.

“Any new character that enters a scene in a drama actually creates a new version of the other characters, because we respond differently,” explains Capaldi. “The Doctor responds differently to Bill than he would to, say, Clara. That means I have to find new ways of doing that character. I have to go to a new place with him. That’s always exciting for me, because the one thing you don’t want to do in a long-running show — even though I’ve only done it three years — you don’t want to get into a groove. You don’t want to get into a place where you think, ‘I know how to do this.'”

Between laughs the actor jokes, “Luckily I don’t know how to do it.” Steven Moffat, the current Doctor Who showrunner who took over in 2008 but plans on stepping down after 2017, wholeheartedly disagrees: “Not true.” Of course Capaldi was only being self-deprecating, but the veteran couldn’t help again stressing that “having someone new like Pearl on the show would certainly help and stimulate” his acting chops. And judging by what Mackie told us about her Doctor Who audition, it seems the pair were able to help one another in precisely the same manner.

“When I first sat down in the room with Steven, Brian, Peter and the casting director in this amazing hotel, I was really nervous. My heart was hammering,” Mackie recalls. “I walked in wearing a baggy t-shirt, jeans, yellow trainers and thought, ‘Oh my God! This is really too nice for me.’ When I read with Peter, everyone was really generous and said they’d loved my first audition. So I figured I would just try and do that again. But reading with Peter was a very different experience. It had a nice bounce to it, and we played off each other really nicely.”

“It was one of those moments where you see something magical come together,” adds Minchin. “We were all trying to keep our poker faces on because Pearl was the first person who’d come in to read with Peter, and we already thought they looked so good together. It worked so well.” Turning to Mackie, the Doctor Who executive producer asks, “You didn’t just sit down and read, did you?”

“No, no we didn’t,” she answers. “The first scene we sat down to read, but in the second scene Peter asked, ‘Do you want to stand up?’ I don’t know if you’ve ever been to a television casting before, but you usually sit down. I usually just try and move my face as little as possible but Peter wanted to stand up, so we did. It was the scene when Bill first goes into the TARDIS and he was bringing me back and forth, pressing imaginary buttons. I was literally thinking this was the maddest thing that had ever happened to me in my life. Luckily that’s what Bill’s supposed to be thinking in the scene — otherwise I don’t know how the audition would’ve gone. It was crazy. The last scene that we read, which was used for the trailer — the one where we’re hiding from the Daleks — Peter had us lean against the wall.”

Whether or not Mackie and Capaldi’s evident onscreen chemistry will translate into 12 episodes remains to be seen. However, considering the Series 10 teaser the BBC released ahead of the Christmas special‘s premiere on Sunday, it’s a good bet the Doctor’s new companion will be sticking around for some time. After all, any earthbound human who can go from serving chips to challenging a millennia-old alien across time and space deserves a central spot in the science fiction program’s storied history. Doctor Who fans haven’t witnessed a character quite like this since Billie Piper’s Rose Tyler in Series One, so it’s high time humanity presented the Time Lord with a worthy partner in crime.

Like Jenna Coleman’s Clara Oswald before her, however, Mackie’s Bill may witness the Doctor’s next regeneration — should Capaldi decide to leave the show in the next few years. In early 2016, rumors swirled suggesting the actor’s inevitable departure after Moffat’s handing over the reins to new showrunner Chris Chibnall. They were quickly squashed by all parties, though the question of Capaldi’s future in Doctor Who still hangs over the actor’s head.

“I love Doctor Who and I love playing the Doctor, so I kind of don’t like to think about a time beyond that,” says Capaldi when asked about the matter. “Clearly when that time comes, however, there are lots of other roles that I’d like to have crack at. I’d like to go back onto the stage for awhile. But we’re very lucky with the people who make Doctor Who. We love it. There’s so many people involved in the production of this show who absolutely love it, so it’s always very difficult to think about not being a part of it. I try not to, at least.”

Moffat, on the other hand, looks forward to the sudden free time letting go of Doctor Who will grant him. As the current showrunner quips towards the end of the interview, he “would quite like to go on holiday, and soon. I’ve mostly been looking at holiday brochures.” Even so, the 55-year-old writer and executive producer isn’t too excited to leave the institution he’s been a part of for over a decade.

“I’ve done nothing but Sherlock and Doctor Who since late 2008. That’s all I’ve written. Nothing else. So I’m certainly in no way wanting to get rid of Doctor Who, and I will miss it tremendously, but it will be interesting to see if I still can write something that isn’t one of those two programs. I’m not thinking about it all that much, though. I’ll be loitering at the door for a painfully long time, and then faltering back into it for the next Christmas special. I’ll be that person who just doesn’t know when to leave.”

Doctor Who returns April 2017 to BBC America. Until then, here’s a preview.