'Outlander' Season 4 News: British Actor Colin McFarlane on Board as Ulysses

The cast for "Outlander" season 4 continues to expand.

Colin McFarlane has joined the Starz time-traveling drama for a key role, according to reports. The U.K. actor will play Ulysses, Aunt Jocasta's butler at her Riverrun estate. Although Ulysses is a slave, he is treated well by Jocasta. He is valued for his exceptional skills and education.

Aside from being Jocasta's personal butler, he also works as a manager of the other Riverrun slaves. He is still around in the most recent book, so he is expected to be part of the series for more seasons.

McFarlane is the third new cast member on board "Outlander" season 4. "Downton Abbey" star Ed Speelers has been recently cast as Stephen Bonnet, a character who is certainly unforgettable to readers of Diana Gabaldon's novels.

Reports point out that the addition of Ulysses is gives an interesting twist to the series, which first introduced the subject of slavery in season 3. Upon arriving at the West Indies, Claire (Caitriona Balfe) is appalled and shocked by the slave trade in the area. She was also surprised at how the men and women on the slave block are treated.

Determined to help, Claire even ended up buying a slave herself just to save him. Season 4 will see Claire witness a very different part of the slave trade once she heads in the colonies — particularly at Riverrun. Future episodes will see her struggle with coping with an era where slavery is normal.

Also joining this coming season is Maria Doyle Kennedy of "Orphan Black" fame. She will take on the role of Jocasta, who is also Jamie's (Sam Heughan) aunt.

On Thursday, on-screen lovers Balfe and Heughan briefly reunited for W Magazine's Celebration of its "Best Performances" Portfolio and the Golden Globes party in Los Angeles.

"Outlander" season 4 premieres sometime this year on Starz.