According to his official agency website, Gareth Roberts will be one of the writers for the fifth series of Doctor Who which is scheduled for transmission next year. On the website, his portfolio has recently been updated with information stating that he will write one episode for the series which will see Matt Smith take on the role of the 11th Doctor and Steven Moffat become the programme's head writer. Gareth Roberts has previously written episodes for both Doctor Who and The Sarah Jane Adventures and most recently helped Russell T Davies co-write the latest episode of Doctor Who which was titled Planet of the Dead. He will also be contributing some scripts for the upcoming third series of The Sarah Jane Adventures and you can view more information about his writing career here. It should however be noted that this news hasn't been confirmed by the BBC at the moment so it is best that it is taken with a pinch of salt. More information will be posted here on this site as soon as it becomes publicly available.