Doctor Who Stars Preview 'Foundling' Bond, Ruby Mystery And 'Devastating' Finale: 'The Stakes Are So High!'

Stellar guest stars, frightful foes and, of course, the timey-wimiest of adventures await the Fifteenth Doctor and his brand-new companion, Ruby Sunday, when Doctor Who lets fly with "Season 1" this Friday at 7/6c, on Disney+.

Sex Education's Ncuti Gatwa made his franchise debut at the close of the Dec. 9 special "The Giggle," then took control of the TARDIS for the Dec. 25 outing "The Church on Ruby Road." In the latter special, he and we met Millie Gibson's plucky Ruby Sunday, who as a newborn had sadly been left on the titular church's doorstep on Christmas Eve 2004.

But as "The Church on Ruby Road" neared its close, a trip back to the fateful night in 2004 raised questions for the Doctor, about Ruby's increasingly mysterious parentage....

In the TVLine video Q&A above, Gatwa talks about how more and more clues about Ruby's past will be scattered throughout the season, while Gibson herself shares her spoiler-free reaction to the upcoming reveals, as she learned of them.

"It's gorgeous to have that connection with the Doctor, the 'lost child' element," the English actress says, echoing showrunner Russell T Davies' own thoughts. "It was really special."

Gatwa and Gibson both get quite animated when hyping some of their favorite guest stars from the season ahead, including Jonathan Groff (Mindhunter) in what has been described as "a key role," and RuPaul's Drag Race champ Jinkx Monsoon as a discordant villain dubbed Maestro.

"[Jinkx] came in for the read-through and my and Millie's jaws just dropped," Gatwa recalls. "Her energy was full. Such a delicious character!"

Gibson next shares how she was not at all prepared for how demanding — physically and musically — her role as Ruby would be ("That wasn't in the audition!" she laughs), after which she and Gatwa name their favorite of many fabulous wardrobe moments.

The conversation closes out with talk of the season's scariest and/or most unsettling moments. Episode 2, "The Devil's Chord" (ft. Monsoon and a reality in which the Beatles were, well, awful), is "pretty unhinged!" avows Gibson, while Gatwa teases the season finale as no less than "devastating."

"These stakes are so high," he says of the finale, which in turn featured "a lot of hard scenes" for the cast to play.

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