Ms Katona is one of several celebrities featuring in Iceland adverts
Supermarket Iceland has sacked Kerry Katona from its advertising campaigns, saying it was "impossible" for her to continue in the role.
The move follows allegations in the News Of The World that the former member of pop group Atomic Kitten was taking Class A drugs.
Ms Katona has featured in the ads for four years, since she won the TV show I'm A Celebrity, Get Me Out Of Here.
The firm said that it would help her get support if she needed its aid.
An Iceland spokesman added that for "most" of her time working for the chain, she had "been a successful part of our advertising campaigns".
"But she has also been through some tough times in her personal life," they added.
"We have always stood by her, as an example of a normal person and mum who has experienced some of the modern-day culture of fame, and how difficult it can be to deal with.
"However, following the most recent allegations, we feel it is impossible for Kerry to continue to work with us as one of the faces of Iceland advertising."
Ms Katona's former publicist Max Clifford, who brokered the supermarket deal, said he thought Iceland had been "very supportive".
He added: "She has reached rock bottom... I am hoping that this will bring her to her senses."
Iceland uses several celebrities to promote its food, including Loose Women presenter Coleen Nolan.
Bookmakers William Hill have named celebrity mums Charlotte Church, Suzanne Shaw, Carol Vorderman, and Kym Marsh as possible replacements.