Jean Marsh, the Emmy award-winning actor who co-created and acted in the ’70s British drama series “Upstairs, Downstairs,” died Sunday in her London home. She was 90.

Marsh’s death was confirmed by The New York Times, with the cause being complications of dementia, according to filmmaker and close friend Michael Lindsay-Hogg.

Marsh co-created “Upstairs, Downstairs” with actor Eileen Atkins. Marsh ended up playing Rose Buck, the house parlor maid, throughout 54 episodes of the show from 1971-1975. She also reprised her role in the 2010 continuation of the series.

For her on-screen work, Marsh won a Primetime Emmy in 1975 in the outstanding lead actress in a drama series category. The original run of the show took home seven Emmys and a Peabody Award. In total, Marsh was nominated for four Emmys throughout her career, including for her work in the “Upstairs, Downstairs” reprisal.

Over the years, Marsh starred in numerous films and shows,...