The British and Irish prime ministers are to travel to Stormont for the restoration of power-sharing on 8 May.
The two prime ministers will be back in NI on 8 May
Tony Blair and Bertie Ahern will witness the creation of a new executive, almost five years after the previous institutions were suspended.
Devolved government is to return to Northern Ireland after the DUP and Sinn Fein agreed last month to share power.
DUP leader Ian Paisley and Sinn Fein's Martin McGuinness will become first and deputy first ministers respectively.
It emerged that Mr Paisley had issued an invitation to Mr Blair to visit Stormont next month.
He told the House of Commons it was Mr Blair's "duty" as he had worked so hard to create the new executive.
When the executive meets, Sinn Fein will assume the education ministry - for the second time - along with regional development and agriculture.
The DUP are taking finance, economy, environment and culture.
The Ulster Unionists take health and employment and learning, while the SDLP take social development.
The power-sharing institutions were suspended in October 2002 amid allegations of intelligence gathering at Stormont. Direct rule has been in place since that date.