Volunteers for the London 2012 Olympics and Paralympics will be given the chance of a sneak preview of the opening ceremony.
London 2012 chief executive Paul Deighton said thousands of the 70,000 'Games Makers' would be invited to attend the dress rehearsal for the ceremony which is being designed by film director Danny Boyle.
Deighton said: "We are not able to get everyone in and we are looking at a number of groups being given a chance so we are finalising how many can come to the rehearsal, but it will be a sizeable chunk, thousands not hundreds."
He also confirmed that volunteers will receive no payments or travel expenses. The first training events for volunteers will be held this weekend with 40,000 due to attend three-hour-long sessions at Wembley Arena.
Of the 70,000, some 3,000 will work alongside security staff at entrances to venues preparing visitors to go through scanning machines.
Organisers have a reserve pool of 15,000-20,000 people in case of drop-outs but Deighton said they are expecting there to be more of an issue with volunteers turning up when they are supposed to be on a day off.
At the last Olympics in Beijing, some venues were noticeably over-staffed by volunteers and London 2012 have spent time making sure staff levels will be correct.
"If you don't have the correct balance then you can have boredom setting in," added Deighton.
"We know that if we do not focus on that we can get attrition."
The volunteers will work eight-hour shifts for 10 days during the Games.
