Cherie Blair is speaking in her capacity as a lawyer

The prime minister's wife has joined Bill Clinton, Henry Kissinger and Bono on the books of the New York-based Harry Walker lecture agency.

A spokeswoman at her Matrix Chambers said she would speak on issues "within her professional expertise" as a human rights lawyer.

Mrs Blair, also known as Cherie Booth, is to visit the US in October.

Fees for an appearance with the agency are reported to go from £25,000 to £160,000 for Mr Clinton.

Details of the tour emerged in a leaked e-mail apparently sent to potential clients of the agency, the Daily Telegraph reported.

It said: "I have exciting news. Cherie Blair, noted British attorney, human rights advocate and the wife of Prime Minister Tony Blair, has agreed to speak under our auspices this fall for a limited number of engagements."

The e-mail is said to quote Mr Blair saying his wife "is an enormous source of strength and an extraordinary person in her own right.