 In May 2019,Duff joined the cast of Harry Potter and the Cursed Child in the London West End production appearing as Professor McGonnigle and the Trolley Witch in the multi award-winning show

Duff is married to former police officer Tom Forrest and became stepmother to his two daughters Sarah and Katie.She met Forrest, a widower, when she bought her sister's house in Burnside in Rutherglen in 1997 and became his neighbour.They were engaged in October and married on 22 March 1998 at Culzean Castle, Maybole He left the police force and set up the property company, Blue Door Property.