Michelle Ryan (born 22 April 1984 in London) played Lady Christina de Souza in Planet of the Dead. Born only a few weeks after Colin Baker's debut as the Sixth Doctor, Ryan is best known in the UK for her work as Zoe Slater on the soap opera EastEnders, and for co-starring in Steven Moffat's miniseries, Jekyll. She also played Nimueh in BBC One's fantasy drama Merlin, in 2008. In North America, Ryan is best known for portraying a reimagined version of iconic TV superhero Jaime Sommers on the short-lived NBC series Bionic Woman in 2007. NBC also broadcast Merlin during the summer of 2009. Reportedly, Ryan was considered a candidate for the companion to follow Rose Tyler. In January 2009, before it was announced that she had been cast in the special, there was considerable media speculation suggesting that she might be the Eleventh Doctor's first companion. Ryan has maintained her connection to the franchise, however, recording the Tenth Doctor exclusive-to-audio story The Rising Night for BBC Audio, which was released in July 2009. She has also occasionally been involved with Doctor Who personnel in other projects. She co-starred with Billie Piper in Mansfield Park; with Lynda Bellingham in Mister Eleven; with Colin Morgan and Anthony Head in Merlin; with Noel Clarke and Russell Tovey in Huge; with Noel Clarke and Nicholas Briggs in 4,3,2,1; with Simon Callow in No Ordinary Trifle; and with Claire Bloom, Michael Maloney, Bonnie Langford and June Whitfield in the Miss Marple mystery, By the Pricking of My Thumbs. She also appeared with Peter Davison in an episode of Death in Paradise.

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