London (CNN) -- More than 40,000 people are expected to attend the official opening of the Olympic Stadium for the 2012 Games in east London on Saturday.
Dozens of celebrities are also taking part in the event, dubbed "2,012 Hours to Go," which begins at 7 p.m. local time (2 p.m. ET).
Two of Britain's most celebrated Olympians, rower Sir Steve Redgrave and swimmer Mark Foster, will be among those present to mark the venue's official opening.
The spectators will watch the last 90 minutes of an athletics championship for British university students, a test event held at the stadium.
Some of the country's best athletes will then take part in invitational events, the organizers said.
The sporting events will be followed by a series of stunts, games and competitions involving celebrities and athletes, including a bicycle relay challenge and "zorbing," where people roll around inside giant transparent plastic balls.
One member of the audience will win the chance to officially open the stadium.
Seb Coe, chairman of organizing committee for the London Olympics, said it was an important milestone in the runup to the Games, now less than three months away.
"Seeing athletes on the track for the first time will be a special moment for me personally, and then welcoming 40,000 people into the Stadium on Saturday night will be a major milestone," he said in a statement.
"This crowd will not only be starting their Olympic journey just weeks ahead of the Games, they will also play a vital role in helping us test the venue and earn our license to operate the Stadium."
Those arriving at the four entrances to the Olympic Park will pass through airport-style security, with metal detectors and bag scanners in operation.
The stadium will host the four opening and closing ceremonies for the Olympic and Paralympic Games, as well as many of the events.
With waterways on three sides, spectators will access the 80,000 capacity stadium via five bridges.
The structure was built using 10,000 tons of steel, considerably less than for other Olympic stadiums, the organizers say, and with an emphasis on sustainability.
Construction began in May 2008 and was completed in March 2011, when the final piece of turf was laid.
CNN's Erin McLaughlin contributed to this report.