The Queen will shake hands with the Stormont deputy first minister on Wednesday. Mr. McGuinness is a former IRA commander and the gesture which will herald another milestone in Anglo-Irish relations.
"This is about stretching-out the hand of peace and reconciliation to Queen Elizabeth who represents hundreds of thousands of unionists in the north.
"I am an Irish republican now - after I meet with Queen Elizabeth, I will still be an Irish republican, and just as passionate about freedom, justice and peace, and reconciliation, as I was the day before."
In an historic encounter, the Queen has shaken the hand of Sinn Fein's Martin McGuinness.
Today's handshake between the Queen and former IRA commander Martin McGuinness is a historic gesture of peace. Here are some others.
The hands of history? The Queen and former IRA Commander Martin McGuinness will make a remarkable gesture for peace today.