The "At home with Aga" campaign is the first work from Cogent Elliott following its account win in May, when it fended off competition from four other agencies.
The campaign features Mary McCartney's photo portraits of celebrities relaxing at home with their Aga in poses that aim to look casual, informal and personal.
Along with Alex James and Sophie Conran, McCartney's subjects also include fashion model Jasmine Guinness, with more planned in the series in the coming months.
The campaign is part of a seasonal push by Aga in the pre-Christmas sales period and also includes digital and direct marketing along with retail support in nearly 100 Aga branded shops around the country.
John Dabb, marketing manager at Aga, said: "We wanted to show the Aga in real-life settings rather than a glossy studio set. This new campaign is designed to appeal to existing Aga converts but, more importantly, brings new people into the brand."