Kate O'Omega was the actress who played the Rani, though it's highly likely that she was actually the Rani in disguise all along. She was so good at acting that she could flawlessly impersonate those who were bad at acting. She appeared in one canon Doctor Who story, two non canon stories, and an audio. She was up for doing more, but died a few weeks before recording, but she gave Briggs the green light for them to get someone else to do the job for her.