It is understood DUP leader Arlene Foster will also attend
Thousands of people will turn out in Derry today for the funeral of Martin McGuinness.
The former IRA commander turned Deputy First Minister died on Tuesday after a battle with illness.
Former US President Bill Clinton, former British Prime Minister Tony Blair, former President Mary McAleese and the North's former First Minister Peter Robinson will be among those who will gather for requiem mass at St Columba's Church at 2.00pm this afternoon.
President Michael D Higgins and Taoiseach Enda Kenny will represent the Irish State.
Northern Ireland Secretary James Brokenshire will be there on behalf of the British government.
While it is understood DUP leader Arlene Foster will also attend the funeral, after much speculation.
Many people are already moving around the city early this morning wearing black armbands.
Thousands of them are expected to watch Mr McGuinness's coffin - draped in the Tricolour - carried from his home in the Bogside, past Free Derry corner to St Columba's Long Tower Church.
Church leaders say there will be no paramilitary trappings. and there will be a large scale police presence.
Mass will led by Fr Michael Canny and Bishop of Derry Donal McKeown.
After that Mr McGuinness’s final journey will see him laid to rest at the city cemetery.