Jo Martin played Ruth Clayton/Fugitive Doctor in the Doctor Who television stories Fugitive of the Judoon, The Timeless Children and Once, Upon Time. alongside Jodie Whittaker's Thirteenth Doctor. She was the first non-white actor to be cast in the role of the Doctor proper in the DWU.
In an interview with DWM 549, she mentioned that she had watched the show as a child, and had always wanted a part on the show.
At the time of her Doctor Who appearance, Martin was perhaps better known as Max McGerry in the hospital drama series Holby City (1999–ongoing).