Mark Papermaster, formerly a big cheese at IBM, has been announced as the new head of Apple's iPod and iPhone development team.
But IBM is none too happy about the appointment and is going to court over it.
Papermaster was vice president of IBM's Blade Development unit, which develops powerful computers for corporate data centres, but has now been nabbed to become Apple's senior vice president of Devices Hardware Engineering.
He hopes to replace Tony Fadell, who will stay on as an adviser to chief exec Steve Jobs.
But IBM has other ideas and is trying to prevent Papermaster taking the job claiming that as a top manager, he had access to IBM secrets and that he had agreed not to work for a competitor for a year.
IBM spokesman Doug Shelton told Reuters: "Mr. Papermaster's employment is a violation of his agreement with IBM against working for a competitor should he leave IBM. We will vigorously pursue this case in court".