Laurence Fox has joined the cast of "Victoria".
ITV have confirmed the 39-year-old actor will portray Foreign Secretary Lord Palmerston in the next instalment of the drama, and Kate Fleetwood will take on the role of Queen Victoria's (Jenna Coleman) mysterious sister Feodora.
Tom Hughes will reprise his role as Prince Albert in the upcoming third series and John Sessions will play Prime Minister John Russell.
Daisy Goodwin, who created and co-wrote the first two seasons, said: "Victoria and Albert are the most famous couple of the nineteenth century, but underneath the united facade, their relationship is at breaking point and it is a struggle for mastery that neither side can win."
Lily Travers is to portray the Duchess of Monmouth, and Nicholas Audsley, David Burnett and Emily Forbes will join the cast as new characters in the eight-part series.
Daisy confirmed in December that a new season had been commissioned and will include "more drama than ever before".
She said at the time: "Series three will start in 1848 which was a hugely dramatic and eventful time for both the royal family and Europe, with revolutions on the continent and uncertainty around the monarchy.
"Viewers can expect more drama than ever before in the third series."
The new series will depict the British monarchy's struggle through the 1848 revolution.
Daisy previously said: "If there were to be a series three, it would include the revolution which was sweeping across Europe, in 1848, and Victoria and Albert think they're going to lose their throne.
"Albert and Victoria will face a very difficult path emotionally, and personally.
"And there will be lots of surprises, and new characters that you might not know about, and that people won't be expecting. And an interesting new political dynamic.
"I think it will be will all change."