Tony and Cherie Blair have confirmed their presence for Margaret Thatcher's funeral on Wednesday.
The couple will be among a number of high-profile guests expected to attend from across the world.
Planning is under way for the ceremonial funeral, which will have full military honours, at St Paul's Cathedral, next Wednesday, under an operation dubbed True Blue.
On Tuesday Buckingham Palace confirmed that the Queen and Duke of Edinburgh will attend - it is the first time the Queen has attended the funeral of a prime minister since Winston Churchill's in 1965.
A spokesman for Labour former prime minister Gordon Brown and his wife Sarah said the couple would be attending the funeral.
But Brown was unable to attend Wednesday's recall of Parliament because of a prior commitment, he said.
The spokesman added: "Sadly and unavoidably Mr Brown had to honour a commitment and was unable to change the day or time of a long-planned speech in France in his capacity as United Nations Special Envoy for Global Education on education and child poverty."
Ten members of staff from the Ritz hotel, where Baroness Thatcher died on Monday, have also been invited to her funeral as thanks for the care she received.