Gemma Chan guest starred in The Waters of Mars as geologist Mia Bennett and is perhaps best known for her portrayal of Charlotte in Secret Diary of a Call Girl, in which she starred alongside former Doctor Who companion Billie Piper. The actress has also appeared in Fresh Meat and Sherlock and is set to appear in Channel 4's new sci-fi drama Humans, set in a futuristic world where robots and humans are interchangeable. Her cinematic contributions include Submarine (2011) and Jack Ryan: Shadow Recruit (2014).