We have another confirmed guest star for Peter Capaldi's debut series of Doctor Who, and that is Tom Riley. You may have seen Riley in Da Vinci's Demons or Twenty Twelve, he also starred opposite David Tennant in St. Trinian's 2: The Legend Of Fritton's Gold (no, I didn't watch that either!).Riley will be appearing in a Mark Gatiss scripted episode of series 8. Which one that is, what it's about and what role he's playing are all very good questions. Unfortunately we don't know the answers as yet.Still it's another quality actor added to what is fast becoming a very impressive roster of guest stars for Doctor Who series 8.More Doctor Who news as we get it.Source: Radio Times