There is no doubt that Peter Capaldi’s exit as the Twelfth Doctor in Doctor Who will get heavy for fans this Christmas.

But just in case you had any doubts, companion Pearl Mackie has assured us all that things will be pretty emotional as he regenerates into Jodie Whittaker.

“I’d say have a box of tissues close at hand,” the Bill Potts actress told RadioTimes.com. “As to be expected: it’s Peter’s last episode as the Doctor and my last episode as well.”

The actress became a fan favourite as she made her debut as the Doctor’s latest companion on the last series, and while the Christmas Special looks set to be her last outing, Mackie remained open to the possibility of returning to the franchise one day.

“One of the wonderful things about Doctor Who is that the world of possibilities is endless,” she added, “so I guess, never say never…”

However, despite all these departures in one episode, Mackie ensured us that there are lots of positives in the episode too, especially as it represents a turning point in the series.

“There’s new beginnings – you’ve got new beginnings with [next Doctor] Jodie Whittaker – it’s a great adventure with two Doctors, it’s going to be very exciting, it’s going to be a lovely episode.”

In the special, David Bradley will reprise his portrayal of First Doctor William Hartnell, and Mackie had nothing but praise for the Harry Potter star.

“Yes, I did get to work with him, which was very exciting,” she recalled. “It was amazing working with David, he’s wonderful… He’s such a brilliant actor and a lovely man.

“He’s great in it and very, very like the first Doctor, which is incredible. It’s uncanny.”

Peter Capaldi will make his final appearance as The Doctor in Doctor Who on Christmas Day (December 25) in the episode ‘Twice Upon a Time’. Watch a trailer below: