Omid Scobie, who wrote a book about Prince Harry, says he heard the conversation while an intern in 2002.

Mr Morgan has always denied knowledge of any phone hacking.

Prince Harry is among a group accusing Mirror Group Newspapers of unlawful information-gathering. The newspaper group is contesting the claims.

MGN denies senior executives at the publisher of Daily Mirror, Sunday Mirror and Sunday People knew about the practices and failed to stop them.

It is alleged that journalists from the newspapers obtained private and confidential information about people's lives through a variety of unlawful means between 1991 and 2011 - including accessing voicemail messages on their phones.

Mr Scobie was called to give evidence on day four of a High Court case brought against MGN.

The court heard that as a journalism student, Mr Scobie spent a week at the Sunday People where he claims he was given "a list of mobile numbers followed by a detailed verbal description of how to listen to voicemails, as if it were a routine newsgathering technique".

In a written witness statement describing work experience at the Daily Mirror in the spring of 2002, the royal commentator "recalls during one of those days in the office the editor, Piers Morgan, came over to talk to someone about a story relating to Kylie Minogue and her [then] boyfriend James Gooding".

"Mr Morgan was asking how confident they were in the reporting and was told that the information had come from voicemails," the statement adds.

"I recall being surprised to hear this at the time, which is why it stuck in my mind."

The court was also told there is an invoice from a private investigator firm for £170, addressed to a showbiz journalist at the paper, for "K Minogue".

Mirror Group Newspapers is contesting the cases and has said there is "no evidence, or no sufficient evidence, of voicemail interception" in any of the four claims chosen as "representative" cases.

Andrew Green KC, for the group, accused Mr Scobie of "a false memory" and being a mouthpiece for the Duke and Duchess of Sussex, after co-authoring a book about them - Finding Freedom.

Mr Scobie denied having a "vested interest" in helping Prince Harry.

"What I am doing right now is giving ammunition to the tabloids to continue calling me his friend," Mr Scobie told the court.

The royal correspondent said he did not have Prince Harry's mobile number, adding: "I am a member of the press trying to do my job... what I am doing today is making my life more difficult."

Returning to Mr Scobie's work experience at MGN, Mr Green went on to suggest it was "somewhat implausible" that a student intern, who was only at the paper for about a week, would have been asked to hack phones.

Mr Scobie replied: "I was not a stranger to this [journalist], I had already met them at some events, I knew them through another person.

"The word hack was not used... this was just a journalist telling me how to do something."

Mr Scobie said: "It felt wrong. In the moment you just sit there and listen, it's only as it sinks in that it does not feel right."

He said he did not hack any phones.

Prince Harry is expected to give evidence at the trial in June. He among four people whose claims are being heard in the trial as "representative" cases of the types of allegations facing the publisher. They will also help the court set the level of damages MGN should pay if the claimants win.

Others involved are Coronation Street actors Nikki Sanderson and Michael Turner, known by his stage name Michael Le Vell, and comedian Paul Whitehouse's ex-wife Fiona Wightman.