Bill Clinton and Tony Blair have been invited to attend a ceremony to mark the 10th anniversary of the Belfast Agreement.
The US-Ireland Alliance is organising the event in Northern Ireland in April, and other central players in the deal which paved the way for power sharing in the North are also due at the event.
Ulster Unionist leader Sir Reg Empey is expected, but the North's First Minister, the Rev Ian Paisley - who opposed the agreement, has not committed to attending.
US-Ireland Alliance president Trina Vargo said she hoped the Rev Paisley's DUP would participate.
Other expected to attend are John Hume former leader of the SDLP, whose rapprochement with Sinn Féin was the first step in the peace process. Former US senator George Mitchell, who chaired crisis talks after the near collapse of the peace process in 1999, is also set to attend.
Mr Clinton and Mr Blair have also been invited to a dinner in Dublin to raise money for suicide prevention across Ireland.