New 'Doctor Who' Companion Unveiled

The Time Lord has a new companion.

Pearl Mackie was unveiled by the BBC on Saturday as the latest co-lead in the long-running cult favorite Doctor Who, joining Peter Capaldi in the show's upcoming season 10.

Mackie replaces Jenna Colman, who after four years on the show revealed in 2015 she would be swapping the sonic screwdriver for a bejeweled crown as the lead in the big-budget PBS/ITV royal drama Victoria. Speculation had been rife as to who would be stepping into Colman's time-and-space traveling shoes, with Eastenders actress Rakhee Thakrar among the initial favorites.

"I'm incredibly excited to be joining the Doctor Who family," said Mackie, who is set to play a character called Bill. "It's such an extraordinary British institution, I couldn't be prouder to call the Tardis my home. I always loved stage combat at drama school so I can't wait to get on set and kick some evil monsters into the next dimension!"

Added Capaldi: "It is a genuine delight to welcome Pearl Mackie to Doctor Who. 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."

Mackie, a graduate from the Bristol Old Vic Theater School, is currently performing in the National Theater's West End production of The Curious Incident of the Dog in the Night Time.

The next season of Doctor Who is due to start shooting next month, and will be the last with Steven Moffat as showrunner. Moffat, who also writes and exec produces Sherlock, announced he would be stepping down in January, handing the baton over to Broadchurch creator Chris Chibnall after more than a decade on the show.