O'Mara played the prim and dastardly Caress Morell in the sixth and seventh seasons of ABC's hit 80s soap opera, Dynasty. To U.K. viewers, O'Mara is perhaps more popularly recognized as the villainous Rani of the Doctor Who franchise, in which O'Mara squared-off against the acclaimed sixth incarnation of The Doctor, played by Colin Baker.
Most recently, O'Mara had been working as a stage actor and author in her native Britain, until she was hospitalized for pneumonia in September 2012.
In October, addressing the 50th anniversary of Doctor Who, O'Mara reflected on her role as recurring antagonist:
"If you put a much older woman in Doctor Who, they can identify with it. I think it's quite an interesting concept and if you remember things like Grimm's Fairytales, the older woman is often the villainess, often the terrifying figure - why I do not know, but often she is. I think it's an idea to be exploited."