Her film roles included Alfred Hitchcock's thriller The Lady Vanishes (1938) in which she played Miss Froy, a British spy posing as a governess who disappears on a train.

[3] She married the actor-manager Ben Webster on 3 August 1892 in St Giles's Parish Church, London.

Their only surviving child, a daughter born in New York in 1905, Margaret Webster, was a producer who held dual US and UK citizenship.

[7] In the 1918 New Year Honours, she was made a Dame Commander of the Order of the British Empire (DBE, gazetted under her legal married name Mary Louise Webster) in recognition of her charitable work during the First World War for the Three Arts Women's Employment Fund and the British Women's Hospitals Committee.

[2] She was the first stage and film actress to receive a damehood, along with the opera singer Nellie Melba, who was also thus honoured in 1918.

[2] In 1939, Whitty permanently moved to the United States - although she never became a US citizen; and appeared both on stage and in Hollywood films, usually playing wealthy dowagers.