Richard E Grant to star in Downton
Richard E Grant and Anna Chancellor will join the cast of Downton Abbey for the fifth series of the ITV drama.
Both actors will play guests of the Grantham family. Grant will play Simon Bricker and Chancellor will play Lady Anstruther.
Dame Harriet Walter will reprise her role as Lady Shackleton, alongside Peter Egan as Lord Flintshire.
24 star Rade Sherbedgia will play a Russian refugee who has fled the revolution after World War One.
Chancellor is currently starring in Sky's drama Fleming about James Bond writer Ian Fleming, while Grant is appearing in the new series of US show Girls.
Downton Abbey, which follows the Grantham family and their servants, will return to ITV later this year, after the show's executive producer ruled out the show coming to an end in the near future.
Gareth Neame promised that the fifth series would have "all the usual highs and lows, romance, drama and comedy".
Speculation over the show's future arose when its creator Julian Fellowes told a newspaper he would not be able to continue writing its storylines at the same time as working on his next project - The Gilded Age, described as an American version of Downton Abbey.
Series four of Downton Abbey achieved an average of 11.8 million viewers in the UK.
Last summer it was announced that Oscar-nominated Sideways star Paul Giamatti was joining the cast of Downton, as the "maverick, playboy" brother of Lady Grantham.
He joined the cast for the Christmas special, which was watched by 6.6 million on Christmas Day, rising to 9.4 million once catch-up services were taken into account.