The former US president, Mr Bill Clinton, has said he is "hopeful" that a new round of talks next month can break the political stalemate in the North.
Mr Clinton and his wife, Senator Hillary Rodham Clinton, were guests of the Taoiseach, Mr Ahern, at a dinner last night in Farmleigh House. They paid a courtesy call on Mr Ahern at Government Buildings before the dinner.
Mr Clinton told reporters that he was in listening mode for the visit. He was encouraged by positive statements in advance of the talks by Mr Gerry Adams of Sinn Féin and Mr Peter Robinson of the DUP.
"The talks are coming up in September and I'm kind of hopeful about it. One thing I think is quite interesting. With all this long political stalemate, no-one has seriously suggested that anybody wants to go back to the way it was and I think that's hopeful," he said.
"I also have been kind of encouraged by the comments that both sides have been making leading up to these September talks. So this is a problem time will take care of, if we all keep doing what needs to be done."
The Clintons and their entourage swept into Merrion Street shortly before 8 p.m. A small crowd cheered at the gates of Government Buildings as the couple arrived.
They met Mr Ahern in his private office for almost an hour. Afterwards, they posed for private photographs in the Meeting Room on the Taoiseach's landing in Government Buildings.
There was no statement at a press photocall after the meeting, before Mr Ahern and the Clintons left for Farmleigh.
They were joined at the dinner by the Minister for Communications, Mr Dermot Ahern, and the Minister for Education, Mr Dempsey, and their spouses.
The Minister of State for Foreign Affairs, Mr Tom Kitt, and the Minister of State for Europe, Mr Dick Roche, were also in attendance, in addition to the Attorney General, Mr Rory Brady.
Mr Kitt said the Government had agreed to give €6 million to kick-start an agreement between the Irish aid programme in Mozambique and the Clinton Foundation, the former president's charitable trust. The full commitment will be €40 million over five years. The money will be used for the treatment for AIDS sufferers.
Mr Clinton, who said he was always happy to visit Ireland, played a round of golf at the Royal Dublin club in Bull Island in the afternoon with local and US players.
The couple, who are staying at the Clarence Hotel in central Dublin, are due to leave this morning for Northern Ireland. Mr Clinton has a book-signing engagement in Belfast, while his wife is scheduled to make a speech in Derry.
The couple travelled in a black Volkswagen van. They were accompanied a large number of plainclothes gardaí and US Secret Service agents.
There were six cars in their entourage, five Garda outriders and a Garda jeep.