By James Hibberd
February 14, 2014 at 04:29 PM EST

International sensation Downton Abbey is adding three cast members, including veterans of Doctor Who, Four Weddings and a Funeral and 24.

The period drama has enlisted for its fifth season …

— Richard E. Grant (Girls, Doctor Who), joining the cast as Simon Bricker, who visits Downton as a guest of the Granthams.

— Anna Chancellor (The Hour, Four Weddings and a Funeral), playing the guest role of Lady Anstruther.

— Rade Sherbedgia (Eyes Wide Shut, 24), playing a Russian refugee.

Also, returning guest cast member Dame Harriet Walter will reprise her role as Lady Shackleton, along with Peter Egan, returning as Lord Flintshire.

The fourth season of Downton Abbey set a record for its premiere, averaging 15 million viewers, an increase of 39 percent from last year. The show’s third season still stands, however, as the show’s most-watched season.