Cross-dressing

Cross-dressing was the act of wearing items of clothing commonly associated with alternative genders. As noted by Rose Tyler, Slist Fayflut Marteveerthon Slitheen was a "cross-dressing Slitheen"; though a female, she wore a synthetic skin suit based on the image of the male Ninth Doctor. Rose quipped that Jack Harkness would "love [her]" for that. (COMIC: Doctormania)

A matriarch of the clan Klep-Clotch Slitheen wore a suit made from the skin of Sir Edward Scott Cameron. (AUDIO: Death on the Mile)

The Second Doctor disguised himself as an old woman while hiding from the British in 18th century Scotland. (TV: The Highlanders)

The Third Doctor disguised himself as a cleaning lady while infiltrating Global Chemicals. (TV: The Green Death)

The Thirteenth Doctor technically cross-dressed immediately following her regeneration, as she was still wearing her male predecessor's clothing. (TV: Twice Upon a Time)

Behind the scenes
Tenth Doctor actor David Tennant cross-dressed as he played the role of a female companion to the Doctor, played by, in a comedic sketch as part of an episode of Channel 4's .

Every actor in the role of the Doctor except for William Hartnell and Paul McGann has cross-dressed as part of a role in a TV show or film, while Patrick Troughton, Jon Pertwee, and Jodie Whittaker have done so on Doctor Who itself.