The Taoiseach, Bertie Ahern, is due to give his historic address to the joint houses of the US Congress in Washington today.
Mr Ahern, the sixth Irish leader to address a joint meeting of Congress, has been billing the event as one of the high points of his political career.
He was invited to give the speech by Nancy Pelosi, the Speaker of the House of Representatives.
The address, which takes place at 4pm Irish time, is one of Mr Ahern's last major engagements as Taoiseach before he steps down next week.
He is expected to focus largely on the peace process and to thank the US for its support in ending the Troubles in the North.
Afterwards, he will attend a special lunch organised by the Congressional Friends of Ireland before visiting President George W Bush at the White House.