Cherie Blair has become the latest high-profile figure to lodge a court claim over hacking of her phone.
Lawyers for the wife of former prime minister Tony Blair confirmed they have issued a claim on her behalf, understood to be against News Group Newspapers.
Graham Atkins, of Atkins Thomson, said: "I can confirm that we have issued a claim on behalf of Cherie Blair in relation to the unlawful interception of her voicemails. I will not be commenting any further at this time."
In November Mr Blair's former communications director Alastair Campbell told the Leveson Inquiry into press standards that he believed a story the Daily Mirror published about Mrs Blair's pregnancy in 1999 may have come from hacking.
He admitted he had "no evidence" that journalists intercepted either Mrs Blair's voicemails or those of her lifestyle consultant Carole Caplin, but queried the source of a number of articles about the former PM's wife.
"During various periods of the time that we were in government, we were very, very concerned about how many stories about Cherie and Carole Caplin were getting out to different parts of the media," he told the inquiry.
"I had no idea how they were getting out. In relation to not just Carole, and not just Cherie, but all of us who were involved in the government at that time, all sorts of stuff got out. Some of it may have got out because people who were within the government were putting it out there. Perhaps. That does happen.
"But equally there were all sorts of stories where you would just sit there scratching your head thinking, 'how the hell did that get out?'."
But in January Sunday Mirror editor Tina Weaver told the inquiry that the story in the Daily Mirror came from public relations guru Max Clifford. She said: "The information came in to the then editor, Piers Morgan, and I was his deputy and he asked me to write it. He purchased it from Max Clifford, I think that's a matter of record, and he told Mr Morgan where he received the original information from, I believe."
News of Mrs Blair's legal action comes just days ahead of the publication of the first Sun on Sunday by News International.