Charlotte Church described how she agreed to waive a £100,000 fee for singing at Rupert Murdoch's wedding in exchange for a promise of future favourable coverage in his papers.
The star, dubbed the Voice of an Angel, told the Leveson Inquiry into press standards she was just 13 at the time and wanted to take the money.
But she was persuaded by her management and record company that she should go for the option of being "looked on favourably" by a "powerful man" like Mr Murdoch.
Charlotte, 25, said she accepted that her strategy failed and that the media mogul's newspapers had since been "some of the worst offenders".
Recounting her experiences of press intrusion, the singer cited a News of the World article reporting her father was having an affair and that her mother had attempted suicide.
On another occasion The Sun revealed she was pregnant for the first time before she had even told her family. She suggested the story must have come from phone hacking or other surveillance.
Charlotte was asked to sing at Mr Murdoch's 1999 wedding to Wendi Deng on the media tycoon's yacht in New York.
She said she was given the choice of receiving a £100,000 fee - the biggest she had ever been offered at the time - or receiving favourable publicity from Mr Murdoch's papers in the future.
"Despite my teenage business head screaming, 'think how many Tamagotchis you could buy!', I was pressured into taking the latter option," she said in a witness statement.
"This strategy failed for me. In fact Mr Murdoch's newspapers have since been some of the worst offenders, so much so that I have sometimes felt that there has actually been a deliberate agenda."