Former News of the World royal editor Clive Goodman hacked the phone of Kate Middleton more than 150 times as well as those of Prince William and Prince Harry, a court has heard.
Goodman, who returned to the witness box after weeks of ill health, was accused of being more heavily involved in phone hacking with private detective Glenn Mulcaire in 2005 and 2006 than was previously heard.
In 2006, Goodman and Mulcaire pleaded guilty to hacking phones in relation to royal aides, but jurors were told their activities went much further.
The phone of Kate Middleton, now the Duchess of Cambridge, was hacked 155 times, Prince William's 35 times and Prince Harry's nine times, the Old Bailey trial heard.
Kate was even hacked on Christmas Day 2005, jurors heard.
The details emerged as Goodman was being cross examined by Timothy Langdale, QC, representing former News of the World editor Andy Coulson.
He asked: "I'm going to suggest you had direct contact with Glenn Mulcaire significantly before the time you have told us - that you yourself had been hacking on a much wider scale than you have told this court about."
Goodman said he had not been asked a direct question.
When he was questioned about the three hacked royal aides, the witness said: "I'm not on trial for hacking. I completely agree I hacked these people's phones. They were never put to me individually by anyone in 2006/2007. I am happy to give a full account of every single one of these."
Mr Langdale went on: "Are you telling us you have forgotten that you hacked Kate Middleton 155 times, Prince William 35 times, Prince Harry nine times and all the others. Had you forgotten that?"
He replied: "No, I did not recall the specifics. The CPS have made it clear there are no other hacking charges. I have not forgotten. I did not recall specifics."
Mr Langdale said Kate Middleton was first hacked on October 21 2005. He asked the witness why she had been targeted and if he had tasked Mulcaire to do it.
He replied: "She was a figure of increasing importance around the royal family. There were discussions about her and Prince William marrying, moving in, settling down. She started to receive semi royal status and things were moving on."
Mr Langdale said: "You are telling us Glenn Mulcaire hacked her without any instruction from you? Did you task him to do that?"
He replied: "I do not remember tasking him to do that. It's possible but I do not recall."
Goodman, of Addlestone, Surrey, denies two counts of conspiring with Coulson and others to commit misconduct in public office. Coulson is also on trial for conspiring to hack phones with former News of the World editor Rebekah Brooks, managing editor Stuart Kuttner and others.
The court has heard Goodman went to Coulson in October 2005 to approve his Alexander Project - an extra £500 a week deal with Mulcaire to hack three royal aides close to the young princes.
Goodman told the court that he had to tell Coulson that Mulcaire was the source of the project, saying: "Glenn Mulcaire was such a valuable resource for the paper I had to tell him [Coulson], so I did."
All seven defendants in the trial deny the charges against them.
The case was adjourned until 10am today.