[1] She made her professional stage debut as the maid in Noël Coward's Easy Virtue at the Duke of York's Theatre, London.
Engagements in minor parts followed in The Constant Nymph, tours in Easy Virtue and Hit the Deck, and a repertory season at the Alexandra Theatre, Birmingham.
[1] Her West End roles in the early 1930s were Mrs. Agnew in Five Farthings (1931), the telephone girl in Grand Hotel (1931), Georgina in Stepdaughters of War, Ruth in Dance With No Music (1932), Mrs. Gilbard in Behold, We Live (1933), Susanne in Love For Sale, and Miss Goslett in Coward's Conversation Piece (1934).
[1] In January 1935, Gregg made her first appearance on the New York stage at the Ethel Barrymore Theatre as Hilda James in Coward's Point Valaine.
Later roles included Miss Prism in The Importance of Being Earnest, Freda Caplan in Dangerous Corner, and Grace Torrence in Coward's Design for Living.