Former Ulster Unionist Party leader David Trimble is to take part in an Israeli investigation into last month's raid on a Gaza-bound aid flotilla.
Nine Turkish activists were killed in the operation.
Mr Trimble - a nobel peace prize winner - will join Canadian, Ken Watkin, a former judge advocate general of the armed forces, as international observers to the inquiry.
It comes as EU Foreign minister prepare to discuss the seige of Gaza at a meeting in Luxembourg later.
The White House has described the proposal to set up the inquiry as "an important step forward".