Eimear Cook, the ex-wife of golfer Colin Montgomerie, has told the court about a meeting she says she had with former News of the World editor Rebekah Brooks in 2004.
In Cook's recollection of the conversation, Brooks appears to refer to the practice of hacking voicemail messages.
Brooks and the other defendants deny all of the charges against them.
Cook told the court:
She said it was so easy to do and she couldn't believe that famous people who have all these advisors and they don't know they need to personalise or change their pin code to make them more secure.
The court heard that the meeting took place in September or October 2004 at the home of a mutual friend. The trial continues.
More top news
Katie Price has defended using the n-word on live television after saying it twice on This Morning.
The 'obsessive and manipulative' stalker who cut his ex-girlfriend's throat as deep as her spine has been jailed for life.
A source close to the Labour leader ruled out his participation in any head-to-head debates which do not involve the Prime Minister.