“I’m thrilled to be in Doctor Who and particularly excited to be crossing cosmic paths with Ncuti, as the Doctor, and look forward to creating interplanetary mischief with him. I loved playing Suzie Costello for Russell T Davies in Torchwood so am thrilled to be entering this world again.”
Nothing about her role is known beyond what Russel T. Davies said upon the casting announcement:
“I’m overjoyed to be reunited with Indira after our Torchwood days, and this part is truly spectacular! A whole new audience will be hiding behind the settee when the Duchess unleashes her terror.”
From this brief description, it appears that The Duchess may be a villain. Additionally, the simple name “The Duchess” is very much in line with Time Lord names. Putting these two pieces of information together, we get a potential villainess female Time Lord. The most prominent villainess Time Lord from Classic Doctor Who is The Rani, who has never appeared in NuWho. One additional piece of speculation supports this theory. Varma is half Indian, and The Duchess translated into Hindi is रानी, which is pronounced “raanee” or “raani.” Some fans may find this a bit of a stretch, but it’s an interesting line of investigation regardless.