Warning: Spoilers ahead for Doctor Who season 15, episode 2, "Lux."Varada Sethu's Belinda Chandra has appeared in Doctor Who actors playing more than one role, her dual-casting as Belinda Chandra and Mundy Flynn is pulling way more narrative focus than usual. It's quietly one of season 15's biggest mysteries, although the Doctor's new companion may know more than she realizes.

Belinda is the second companion in a row to arrive with compelling and unanswered questions, as Millie Gibson's Ruby Sunday also filled that role during her time among the Doctor Who season 14 cast. The difference is that Belinda knows who her parents are and has already mentioned them several times. So, what the show needs to solve is why Belinda looks identical to Mundy Flynn, despite the two genetic relatives being separated by 3,000 years. Although the answer hasn't yet been officially provided, Belinda has subtly teased the audience with a quick line of dialogue.

"Let's Go Home To Gallifrey" Could Suggest Belinda Is A Time Lord

Belinda calling Gallifrey "home" could be a big clue

At the beginning of Doctor Who season 15, episode 2, "Lux," Belinda suggests getting the Time Lords involved with their predicament. She is hopeful they can get the TARDIS fixed on "Timelordia," and Fifteen (Ncuti Gatwa) corrects her by telling her the Time Lord home world is called Gallifrey. Belinda phrases her reply very interestingly, as she says, "Let's go home to Gallifrey." The line feels very loaded with meaning beyond a request to head to the planet, as it sounds as though she's also referring to Gallifrey as her home. If so, she could also be a Time Lord.

If Belinda is a Time Lord, then it doesn't seem as though she knows it. As far as she is concerned, she is a human nurse from Earth.

If Belinda is a Time Lord, then it doesn't seem as though she knows it. As far as she is concerned, she is a human nurse from Earth. However, that doesn't necessarily mean that her memory hasn't been toyed with. It's possible that her mind has been wiped by the same device the Time Lords used to erase the Doctor's past before he regenerated into William Hartnell's First Doctor. That said, some part of who Belinda was before this possible mind wipe may have survived the process, and subconsciously led her to refer to Gallifrey as her home in "Lux."

Belinda Being Human Right Now Doesn't Mean She Can't Secretly Be A Time Lord

Doctor Who's Chameleon Arch could have returned

Now, I will it that there are some holes in my theory that Belinda is a Time Lord, but they're not impossible to explain. The Doctor has already taken Belinda's DNA and cross-referenced it with Mundy Flynn's. So, he would know if she were anything other than human, and he'd be especially curious if the TARDIS had flagged her as a Time Lord. She may be human right now, but she may not always have been. David Tennant's Tenth Doctor famously used a Chameleon Arch in Doctor Who season 3 to completely transform his body into that of a human.

The Chameleon Arch also took Ten's consciousness and stored it in a pocket watch, with a false personality named John Smith taking over the Doctor's new human form. Sethu's character could have undergone the same procedure, with Belinda Chandra serving as her current alter ego, just as John Smith was for Ten. Plus, this could explain why Mundy Flynn shares so much genetic material with Belinda. In short, they could be the same character.

Belinda's Time Lord identity could travel through space and time like the Doctor, and then use the Chameleon Arch on herself in various locations as she builds separate lives throughout the universe.

Belinda's Time Lord identity could travel through space and time like the Doctor, and then use the Chameleon Arch on herself in various locations as she builds separate lives throughout the universe. It's unclear what her motivation for such a life would be, but Ten was doing so to keep himself hidden from those pursuing him. Belinda's motivations could be similar, as trying to find a Time Lord is presumably much easier than locating something as common as a human.

Doctor Who's Disney Era Has Quietly Set Up Belinda To Be A Specific Time Lord

The surname "Chandra" has showed up in Doctor Who canon before

If Belinda is secretly a Time Lord, then the twist would be made even more exciting if Sethu were playing a returning Doctor Who character rather than a brand-new one. Interestingly, Doctor Who's classic era, the Rani is a fiercely intelligent Time Lord who quite often verges on being a villain due to her cold desire to further her scientific research. She seems like a specific name to mention if Davies doesn't plan to bring her back.

The Sarah Jane Adventures featured a character called Rani Chandra (Anjli Mohindra).

Furthermore, "Rani" is an Indian word, meaning "queen," and Belinda was referred to as both the Queen of Missbelindachandra and Earth in "The Robot Revolution." Plus, The Sarah Jane Adventures featured a character called Rani Chandra (Anjli Mohindra). There's currently no canonical connection between Belinda Chandra and the Doctor Who spinoff character, but it may not be a coincidence that the signs seem to be pointing toward Sethu playing the Rani, while the franchise already boasts a character named Rani Chandra. It would be a meta clue, but Doctor Who's Disney era hasn't been afraid of breaking the fourth wall.

I Really Hope Doctor Who Season 15 Doesn't Fumble Belinda's Big Twist After The Ruby Disappointment In Season 14

The big reveal of who Ruby's mother was ended up being underwhelming

I hope I'm right about Belinda being the Rani, or another Time Lord, but even if I'm not, I have my fingers crossed that Doctor Who season 15 will include another kind of brilliant twist for Sethu's character(s). The mystery of who Ruby's mother was in Doctor Who season 14 felt like it was setting up a really exciting reveal, but showrunner/writer Russell T. Davies ultimately chose the most underwhelming option possible by revealing Ruby's mother as just an ordinary human. If season 15 does something equally disappointing with Belinda, I can easily imagine the viewers getting disgruntled again.

Thankfully, there appears to be a far more complex storyline in place for Belinda, which leads me to believe that Davies won't do the same thing again by bailing out of a fantastical reveal and providing a very grounded resolution. I probably would rather have had a companion after Ruby who didn't come with all of these unanswered questions, but I've ended up quite liking the intrigue of what's going on with Belinda, and, by extension, Mundy Flynn. Only time will tell what lies ahead in Doctor Who season 15, but I'm hoping I continue to enjoy the ride.