British actress Pearl Mackie has been announced as the new Doctor Who companion.

The 28-year-old will star as Bill alongside Peter Capaldi's Time Lord in the Tardis when the next series airs in 2017. Pearl replaces Jenna Coleman, whose character Clara Oswald left the show in 2015.

The actress, who is currently performing in the production of The Curious Incident of the Dog in the Night Time in London's West End, said she is proud to be a part of the BBC series.

"I'm incredibly excited to be joining the Doctor Who family," Mackie said. "It's such an extraordinary British institution, I couldn't be prouder to call the Tardis my home.

"Peter Capaldi is such a brilliant actor, and his Doctor is such a wacky and wonderful character. I can't wait to see what adventures are in store for him and Bill throughout time and space."

Mackie, whose only screen roles include bit parts in 2013 movie Svengali and BBC soap Doctors, said her character was "cool, strong, sharp, a little bit vulnerable with a bit of geekiness thrown in".

Capaldi, who joined the show as the 12th Doctor in 2014, said his new companion was a refreshing addition to the long-running sci-fi series.

"It is a genuine delight to welcome Pearl Mackie to Doctor Who," he said. "A fine, fine actress with a wonderful zest and charm, she's a refreshing addition to the Tardis and will bring a universe of exciting new possibilities to The Doctor's adventures."

Coleman, who joined the show in 2012, starred alongside two Doctors - Matt Smith and Capaldi. She asked to be written out, and is due to star as Queen Victoria in the eight-part ITV drama series Victoria later this year (16).