Beau Brummell , ( George Bryan Brummell London , 7 June 1778 -- Caen , France , 30 March 1840 ) , was the leader of men 's fashion in Regency England and a friend of the Prince Regent , the future King George IV . Beau Brummell , born as George Bryan Brummell ( 7 June 1778 -- ) , was the arbiter of men 's fashion in Regency England and a friend of the Prince Regent , the future King George IV .