EastEnders star Michelle Ryan got tongues wagging (and in more ways than one!) when she was revealed as Doctor Who's 'companion of the week' Lady Christina de Souza for the 2009 Easter special, Planet of the Dead. Although it was always destined to be a one off appearance, the actress had previously auditioned to play Rose Tyler when the show was casting its 2005 revival. The coveted role was ultimately awarded to Billie Piper who became one of the most popular companions in Doctor Who history. Would Michelle have made the same impact as everybody's favourite shop girl turned Earth Defender? Only a parallel universe somewhere, she's probably doing just that.