Harriet Beauclerk, Duchess of St Albans (alternative spelling: Harriot;[2] née Mellon; 11 November 1777 – 6 August 1837) was an Irish actress who starred at Drury Lane.

She was successively the wife of banker Thomas Coutts and then of William Beauclerk, 9th Duke of St Albans.

Mellon, according to her memoirs published in 1839, was born near Cork in the south of Ireland to parents who were typical cottiers of the period; that is poor Catholic subsistence farmers.

When her village was visited by strolling players (members of a travelling theatre company) she decided upon a life as an actress.

[6] 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 Stratton Street, Piccadilly.