Doctor Who Series 11: which episode features the temple implants?

When the second Doctor Who Series 11 trailer was released, Bradley Walsh was featured in a scene where he has some sort of implant attached to his right temple.

A still from the BBC Doctor Who Series 11 trailer

Behind-the-scenes footage from Access All Areas also show these implants on the right temples of Mandip Gill and Jodie Whittaker.

A still from Access All Areas, Episode 1, BBC Studios

A still from Access All Areas, Episode 1, BBC Studios

I can tell you that, from a few photos that were accidentally posted publicly on the still photographer’s website, it’s the same episode in which Mark Addy appears.

Mark Addy, BBC

Mark Addy, BBC Doctor Who guest star trailer

A still from the BBC Doctor Who trailer

So which episode features the implants? The foremost candidates are Episodes 7, 8, 10 (the series finale), and the Christmas special.