John Simm is set to return as the Master in the upcoming tenth series of "Doctor Who."

The news, announced on the show's official BBC website, might have some casual fans scratching their heads, as the role of the Doctor's greatest Time Lord adversary has been played with gusto and to much acclaim by Michelle Gomez since 2014, and we already know she will be returning this season.

Of course, in the timey-wimey world of "Doctor Who," pretty much anything is possible, and the show has a long tradition of multi-Doctor stories, in which previous incarnations of the Gallifreyan have joined forces. It now seems possible that fans will be getting their first multi-Master story.

RELATED: New"Doctor Who" Promo Teases Twelfth Doctor’s End

Speaking about his return to the show John Simm said, “I can confirm that it’s true, thanks to the power of time travel I’m back. It’s always a pleasure to work with this great team of people and I can’t wait for you all to see what the Master gets up to in the next series.“

It appears that the original plan had been to keep Simm's involvement a surprise, but as current showrunner Steven Moffat, notes, "Nothing stays secret for long on 'Doctor Who' but you'll have to wait a little bit longer to see exactly what the Master is up to and how he makes his return to face the Doctor. It’s been a huge pleasure to have fan favorites John Simm and Michelle Gomez face to face in the same role! It’s not often you get to see a solo personality clash."

RELATED: Doctor Who Gets First Openly Gay Companion

Starring Peter Capaldi as the Doctor, Pearl Mackie as Bill Potts and Matt Lucas as Nardole, “Doctor Who” returns to BBC One and BBC America on Saturday, April 15.