In 1802 she left Drury Lane. She then appeared on the stage of a rival theatre, Covent Garden, from time to time. It was there, on 29 June 1812, that she gave perhaps the most extraordinary farewell performance in theatre history. She was playing her most famous role, Lady Macbeth, and the audience refused to allow the play to continue after the end of the sleepwalking scene. Eventually, after tumultuous applause from the pit, the curtain reopened and Siddons was discovered sitting in her own clothes and character - whereupon she made an emotional farewell speech to the audience lasting eight minutes.