The decision follows the news that Kraft had called in Edelman to provide strategic PR advice on a post-merger scenario.
The agency has already started work on the account, providing "preliminary strategic counsel", said Kraft VP of corporate affairs Nancy Daigler.
Brunswick currently handles the financial communications for Kraft's bid, but Edelman is expected to assume the core elements of its corporate and internal communications now that the bid has been accepted.
The deal raised concerns among the public that the ‘Britishness' of the 186-year-old Cadbury brand would be lost should the merger go ahead. However, Porter Novelli head of crisis, Neil Bayley, said: "I can't see Kraft making any major changes that might risk damaging the value of the brand in the eyes of consumers. Consumers will be sceptical though, particularly here in Britain. This will need careful stewardship as there will be plenty of Cadbury lovers looking to seize on any hint of change they don't like."
A Cadbury spokesman declined to comment on the story.