Harriot Beauclerk, Duchess of St Albans (née Mellon; 11 November 1777 – 6 August 1837) was a British actress who eventually starred at Drury Lane. She was successively the wife of banker Thomas Coutts and William Beauclerk, 9th Duke of St Albans.Mellon was the daughter of strolling players (members of a travelling theatre company) and became an actress. When she was young, she appeared at the Duke Street Theatre, where she attracted the attention of an elderly wealthy banker, Thomas Coutts of Coutts & Co, the royal bank. Following his wife's death in 1815 she married him. She was widely celebrated for her beauty, and was painted by George Romney and Sir Thomas Lawrence.In 1822, after her husband's death, she became very wealthy, have been bequeathed his entire fortune, including his interest in the family bank. She purchased the lease on a country property four miles away at the Holly Lodge in Highgate, holding parties there and at her town house at 78 Piccadilly. She also spent time at her house in Brighton, St Alban's House, 131 Kings Road, on the corner of Regency Square. In 1827 she married William Beauclerk, 9th Duke of St Albans, who was 23 years her junior.On her death in 1837, her property and fortune went to her stepgranddaughter, carefully selected as heir after careful scrutiny of the possible recipients, who as a condition of the inheritance adapted her name to Angela Burdett-Coutts.