The daughter of a Swiss clockmaker, was born in London, and at the age of about fifteen became the mistress of Lord Craven. He was succeeded by the Hon. Frederick Lamb, and by a long series of distinguished lovers and acquaintances, including Lord Hertford (Thackeray's 'Marquis of Steyne'), Beau Brummell, and the Duke of Wellington. About 1820 she went to live in Paris, and being in need of money, partly owing to
'the ill-timed parsimony of the Duke of Beaufort, who thought to compound a promised annuity of £500 by a single payment of £1,200',
she decided to write her memoirs — 'Confessions of Julia Johnstone' (1825).