Asda identified Osbourne, a multi-millionaire, as being representative of mothers and someone its shoppers believe stands for "caring, providing, coping".
The new campaign, "Mums in a million," will show Osbourne, the wife of the rock legend Ozzy, testing out an Asda store and talking to its customers and staff. It will also introduce a new strapline. "Pocketing the difference" replaces "Always low prices".
The move is a departure from previous campaigns by Asda, which have used real-life mums to promote its low-cost positioning.