The 29-year-old Duchess of Cambridge's account was accessed in 2005, when she was just the girlfriend of Prince William, by Jonathan Rees, a private investigator who worked for the 'News of the World', 'The Daily Telegraph' reported.
Other high-profile individuals said to have been targets for Rees, who was cleared of murder earlier this year, include former British Premier Tony Blair, Duke and Duchess of Kent and Metropolitan Police assistant commissioner John Yates who once headed the phone hacking inquiry, the report said.
Rees was named by Tom Watson MP who told the House of Commons yesterday that Scotland Yard had evidence against the investigator but have said it falls outside the scope of their investigation.
Detectives at Scotland Yard are understood to have been in touch with the Duchess of Cambridge to warn her that her bank details may have been accessed. The Metropolitan Police confirmed it had received "a number of allegations" and it was considering investigating.
A Met spokesman said: "Since January 2011 the Metropolitan Police has received a number of allegations regarding breach of privacy which fall outside the remit of Operation Weeting. These allegations are currently being considered."
A St James's Palace spokesman refused to comment.
Deccan Herald is on WhatsApp Channels| Join now for Breaking News & Editor's Picks