The U2 guitarist is suing his accountants and Bank of Ireland Private Banking for several million euro in damages for Adam Clayton.
The musician alleges his former personal assistant Carol Hawkins misappropriated over €4.8m from his bank accounts.
Mr Clayton alleges that his accountants Gaby Smyth & Company assured him in September 2008 that the sum involved was around €13,000.
The U2 star claims it was in fact €4.4m.
The case will be heard at the commercial court on Monday.