Sir Frederick Barclay, who owns the Ritz Hotel with twin brother Sir David, will testify in the trial of three men accused of illegally trying to sell it.
Conn Farrell, 57, Patrick Dolan, 68, and Anthony Lee, 49, are accused of trying to sell the landmark hotel in Piccadilly for £250m.
Sir David's son Howard has also named as one of the 18 intended witnesses in the trial in Southwark Crown Court.
Mr Farrell, Mr Lee and Mr Dolan deny conspiracy to defraud.
Mr Dolan, of Tottenham, north London, Mr Farrell, of Cambridge Road, Aldershot, and Mr Lee, of Broad Lane, Goole, East Yorkshire, are accused of defrauding Terence Collins and Marcel Boerkhoorn between January 2006 and March 2007.
The trial is expected to begin on Tuesday.