Tony Blair is to make his second appearance before the Iraq Inquiry on Friday January 21.
The former prime minister is one of several witnesses to be recalled to give evidence to the inquiry headed by former Whitehall mandarin Sir John Chilcot.
The inquiry said the 60 public seats in the hearing room in the Queen Elizabeth II Conference Centre had been allocated through public ballot, with a third going to family members who lost loved ones in the conflict.
Mr Blair's hearing will start at 9.30am and is scheduled to last around four-and-a-half hours.
Other witnesses who have been recalled include former foreign secretary Jack Straw and former chief of the defence staff Admiral Lord Boyce.
Cabinet Secretary Sir Gus O'Donnell is one of a number of witnesses who have been called to give evidence for the first time in the final round of public hearings.
The sessions start on Tuesday January 18, when former chief of the air staff Air Chief Marshal Sir Glenn Torpy will give evidence.