AceShowbiz -

"Downton Abbey" is losing another of its members. Following the departures of Jessica Brown Findlay and Dan Stevens, Siobhan Finneran who plays Lady Grantham's maid Sarah O'Brien says that she will not return to the fourth season of the Julian Fellowes-created series.

"I'm not doing any more," she tells U.K.'s The Mirror. "O'Brien is a thoroughly despicable human being - that was great to play." A spokeswoman for the show reportedly confirms Finneran's exit, but adds that there is a chance the actress will return someday.

"Downton Abbey" killed off Lady Sybil Branson and Matthew Crawley in season 3 following the actors' (Findlay and Stevens) decisions to leave the show. Explaining the tragic fate of Matthew, Fellowes once said, "Audiences across the world have been captivated by the ups and downs of Mary and Matthew's relationship, culminating in their wedding."

"Fans have enjoyed what has become a solid and loving marriage. It is for this reason that the producers decided Matthew and Mary could not simply be estranged or parted, resulting in his untimely and tragic death at the end of the [season 3] finale."

Recently, the remaining cast of the British period drama was spotted filming what is believed to be Matthew's funeral since they were all dressing in black. Words are, producers have been auditioning actors for the new love interest of Lady Mary with "EastEnders" star Tom Ellis mentioned as a strong contender for the role.