Martin McGuinness has said he believes he will be in government on Monday with Ian Paisley and suggested they should have the same kind of working relationship as Nelson Mandela and FW de Klerk.
As the last big push was being made for devolution, US president George W Bush yesterday had telephone conversations with Mr Paisley and Sinn Féin president Gerry Adams.
The DUP leader also had discussions with Prime Minister Tony Blair at Westminster, who said the government will stick rigidly to Monday's deadline for forming a power-sharing executive.
In an interview with The Irish News, Mr McGuinness said he and Mr Paisley had long been bitter political opponents but he "wants to work normally with him".
The Sinn Féin chief negotiator said the north was on the verge of "a monumental political breakthrough", which he described as "probably the biggest political development since the 1916 Rising or the partition of Ireland".
He said he believed he will be sharing the Office of the First Minister and Deputy First Minister on Monday with Mr Paisley.
"I want to work normally with Ian Paisley. I want to do the business with him. Will we ever be bosom buddies? I don't know... let's try," he said.
The Mid-Ulster MP said the "war is over" and political opponents had to make the effort to work together.
He said he remembered former South African leader FW de Klerk coming to the Forum for Peace and Reconciliation in Dublin and talking about his relationship with Nelson Mandela.
"He never imagined the day when they would invite each other out to dinner or to each other's houses," he said.
"I don't imagine Ian Paisley and I will have that type of relationship.
"But if we have the type of relationship that Nelson Mandela had with F W de Klerk... and we deal with the political business that affects all our people... and we do that in a way that produces results, then that is all that people expect.
"They don't expect us to put our arms around each other and have a lovey-dovey relationship."
Republicans have often drawn parallels with political struggles in Ireland and South Africa.
FW de Klerk was once a supporter of racial segregation but after assuming leadership in South Africa in the 1980s lifted the ban on the African National Congress, released Nelson Mandela from prison, and they began to work together politically.
Meanwhile, Mr Paisley will join other party leaders today (Thursday) including Mr Adams, UUP leader Sir Reg Empey and SDLP leader Mark Durkan for talks with chancellor Gordon Brown about an economic package to underpin the work of a new executive at Stormont.