She was born, by her own account, at Fingal, Ireland. "George Anne" was a name given by mistake for Georgiana. She was the illegitimate daughter of James O'Hara, 2nd Baron Tyrawley, and was educated by him. Choosing, however, to live with her mother, she made the acquaintance of Mrs. Woffington and other actors and was engaged at Covent Garden to play Monimia in The Orphan (November, 1744). Her success thereafter was rapid. She participated in the rivalry for popular favor in Romeo and Juliet in 1750, playing with Garrick at Drury Lane, while Barry and Mrs. Cibber played at Covent Garden. She was thought the more charming of the Juliets. Mrs. Bellamy was extremely popular, and until she forfeited her character by her various liaisons, was received in the best society. She lost her beauty early, and her later life was unhappy, apparently through her own extravagance and reckless habits. Her last appearance was at Drury Lane on 24 May 1785 in a benefit to herself, in which she was unable to act, but spoke a short address to the audience.