TOM MARVOLO RIDDLE      A mysterious former Hogwarts student who magically appears from within the pages of an old diary discovered by Harry, Tom was a Head Boy who was presented with a special award for service to the school several decades ago.    One of the UK's fastest rising young stars, CHRISTIAN COULSON, joins the cast as a mysterious and ghostly ex-Hogwarts student.    A recent graduate from Cambridge University, this is Coulson's third feature film, having featured in the role of Ralph in Stephen Daldry's The Hours and the role of the Drummer boy in Shekah Kapur's Four Feathers.    He is also currently starring as Jolly in ITV's epic drama The Forsyte Saga and played the role of Matt in BBC TV's Love is a Cold Climate.    Coulson's talents first came to light while studying at Cambridge University with memorable performances including: the role of Emcee in Cabaret; the role of Arturo Ui in The Resistable Rise of Arturo Ui and curiously the role of 'Claire' in The Maids.