Heather Mills McCartney is to sue two newspapers over "false, damaging and immensely upsetting" claims surrounding her divorce from Sir Paul McCartney.
The couple married in Republic of Ireland in 2002
Legal proceedings will be taken against the London Evening Standard and Daily Mail, lawyers for the 38-year-old said.
Solicitors Mishcon de Reya added that legal action will also be taken against The Sun.
In a statement, Mishcon de Reya asked the media, on behalf of Lady McCartney, to "show some restraint".
Lady McCartney, the lawyers said, had been vilified in the media, and was being "stalked" by photographers.
The statement said: "It would appear that the media has concluded that there are no limits to what may be said about, or done to, our client."
It added: "She is stalked by press photographers, who congregate outside her home and chase after her in cars - regardless of her safety or the safety of her daughter."
Mishcon de Reya said Lady McCartney could not afford to sue all the newspapers she wanted to.
"Her time and resources are not infinite. She cannot sue - for now, at least - every single newspaper that has published false, damaging, and immensely upsetting statements about her.
"She should not thereby be taken to have accepted that these statements are true."
The lawyers also issued a copy of a letter they said was from The Mail on Sunday's investigations editor Dennis Rice, offering Lady McCartney's sister Fiona a "substantial sum" for information about the divorce.
'No settlement offer'
The latest storm over the couple's increasingly acrimonious divorce began last week when legal papers containing allegations that Sir Paul mistreated Lady McCartney during their four-year marriage were leaked to the press.
The musician strenuously denied the claims, adding he would "vigorously" contest the allegations in court.
Mishcon de Reya also said that claims Lady McCartney had been offered a £30m divorce settlement from Sir Paul were "entirely false".
"The truth is that no settlement offer, in any amount, has been made," the statement added.