Her acting role model is Susan Sarandon.
First actress to serve as an original model for Eidos Interactive's Lara Croft (Tomb Raider).
She is the daughter of Nora (Downey), who is of Irish origin, and Anthony Mitra, who is of Bengali Indian and English descent. They divorced in 1984.
Decided she wanted to be an actor at 9 years old when she met Judi Dench, mother to one of her classmates. "She came to pick her up from school and I remember meeting her and I thought she was such an extraordinary woman. She had this resonance about her. I said, 'What does your mummy do?' and I logged it away" - H Magazine.
Went to Roedean, an all-girls' school in Brighton, East Sussex, but was expelled from it, then from another boarding school. According to Rhona, "I was kicked out for taking a sixth-former's car and driving it down to the local boys' school. I was only 14. I left stuffing under my bedsheets but one of my friends told on me and the headmistress tracked me down. They put me in this room with bars on the windows to punish me. I was stuck in there for a whole week with just a rosary for comfort, having my dinner brought in on trays. The only time I got out was to say confession to the school priest. After that, they booted me out. Then at the next school the other girls used to blame me whenever they got caught for something, so all the parents wrote in and said they didn't want me at the school. I crammed my exams in London and did fine."