Joanna (Zygon: When Being You Just Isn't Enough)

Joanna was a physician at St Kitts Hospital, where she also dated her supervisor M. R. Samms. They conspired to get rid of Lauren Anderson by encouraging her to take a holiday, but she got back at them by using her new Zygon powers to impersonate Joanna to have sex with Samms.

Joanna was later present when Torlakh disguised himself as Lauren to frame her for murder, watching in horror as he killed Samms before she fled the scene. (HOMEVID:  Zygon: When Being You Just Isn't Enough)