Tony Blair, Bertie Ahern and former US senator George Mitchell will attend a conference in Belfast next week marking the 25th anniversary of the Good Friday Agreement.
They are among the architects of the 1998 peace deal taking part in the event at Queen’s University.
Mr Mitchell chaired the negotiations which led to the agreement, while Mr Ahern and Mr Blair were taoiseach and British prime minister at the time.
Mr Blair's wife, Cherie, will also attend the conference and take part in a Women In Business event.
Bill Clinton, US president in 1998, and his wife Hillary will also attend, along with former taoiseach Bertie Ahern.
Queen’s University vice-chancellor Professor Ian Greer said: “It is another major coup to have secured two more of the key architects in achieving the peace that we continue to enjoy for the Agreement 25 conference.
“Senator Mitchell has expressed his immense attachment for Northern Ireland and his return will be an emotional visit for many of us.
“We will have the honour of unveiling a bust in his honour in the grounds of the university which will further cement the great relationship senator Mitchell has had with Queen’s University.
“We also welcome Tony Blair who will contribute to the Guaranteeing Peace – The Guarantors section of our conference.
“Joining former US president William J, Clinton and former taoiseach of Ireland Bertie Ahern, he will reflect on the magnitude of the agreement, how it was reached and the impact it has had on Northern Ireland.”
A number of events have been taking place in Northern Ireland marking the anniversary of the agreement which largely led to the end of the Troubles and established the powersharing Assembly at Stormont.
US president Joe Biden delivered a speech at Ulster University on Wednesday in which he expressed hope for a return to powersharing, saying a stable devolved government could deliver an economic windfall for the region.
The institutions are currently suspended as part of a DUP protest against post-Brexit trading arrangements.
Mr Biden said: “As a friend, I hope it’s not too presumptuous for me to say that I believe the democratic institutions established in the Good Friday Agreement remain critical for the future of Northern Ireland.
“It’s a decision for you to make, not for me to make, but it seems to me they are related.”
Last week a ceremony at Stormont on Good Friday marked the anniversary.
In a video message at that event, Mr Mitchell urged current political leaders to act with the same “courage and vision” as those who secured the Good Friday Agreement.
