- (1930 - 1940) Played Hercule Poirot in Agatha Christie's 1930 play "Black Coffee" (later filmed as Black Coffee (1931) with Austin Trevor) and her 1940 play "Peril at End House". "Peril at End House" was filmed for television many years later as part of the "Agatha Christie's Poirot" series, with David Suchet as the famous detective.
- (1954) Played Sir Wilfrid Robarts in the original Broadway production of Agatha Christie's "Witness for the Prosecution" in 1954.
- Eventually replaced Nicholas Joy as Pothinus in the 1949 Cedric Hardwicke-Lilli Palmer Broadway revival of "Caesar and Cleopatra", repeating his role from the 1945 film version.
- (1933) He acted in Campbell Dixon and Dermot Morrah's play, "Caesar's Friend," at the Piccadilly Theatre in London, England, with D.A. Clarke-Smith, Gillian Lind, Robert Speaight, Richard Goolden, and Dorothy Drake in the cast. Robert Atkins was director.
- (1936 - 1937) He played Claudius in William Shakespeare's "Hamlet" at the Old Vic Theatre in London, England, with Laurence Olivier, Michael Redgrave, Alec Guinness, Marius Goring, Robert Newton, Dorothy Dix, and Cherry Cottrell in the cast. Tyrone Guthrie was director.
- (1931) He acted in Edward Lewis's stage adaptation of Mary Webb's novel "Precious Bane" in a two-week engagement at the Embassy Theatre in London, England, with Donald Wolfit, Robert Donat, Andre Van Gysegham, Edith Sharpe, Richard Caldicot, and Joyce Bland in the cast.