LONDON (CNN) - Few shows can claim such an audience. As the dramatic spectacle of the Olympic Games opening ceremony in London unfolds Friday night, organizers estimate a billion people around the world will be glued to their television sets.
Tens of thousands more are lucky enough to have a seat inside the Olympic Stadium, the centerpiece of the Olympic Park in east London.
Dubbed Isles of Wonder, it promises to be quite a show -- but then it needs to be.
The opening ceremony, attended not only by thousands of athletes but also Queen Elizabeth II and more than 80 visiting heads of state, the government says, sets the scene for the Games to come.
And the organizers of the London Games are well aware they have a tough act to follow after the Beijing extravaganza four years ago, which featured thousands of drummers, acrobats, martial artists and dancers performing under a light display at the soaring "Bird's Nest" Stadium.
So what can those watching the ceremony this time around expect to see?
Some details of the £27 million show have been released already, but many more remain a closely guarded secret.
Keeping a secret this big isn't easy, though, when there are thousands of performers and technicians involved, not to mention the audiences for two dress rehearsals this week.
A Twitter hashtag, #savethesurprise, started by Olympic organizers to appeal to those in the know not to spoil the show for others, has been embraced by many, although not all.
Giant screens also displayed the message within the stadium during the rehearsals. Those who opted not to play along have incurred the social-media wrath of many who do want to "save the surprise."
What the organizers have revealed already is that the show, masterminded by artistic director Danny Boyle, best known for the Oscar-winning film "Slumdog Millionaire," draws its inspiration from Shakespeare's "The Tempest."
It will begin at 9 p.m. local time (4 p.m. ET) with the tolling of the largest harmonically tuned bell in Europe, cast by the nearby Whitechapel Foundry, which also produced Big Ben and the Liberty Bell. The sound will echo the peals of bells that rang out across the country for three minutes Friday morning, Big Ben among them, to set the nation's Olympic spirit racing.
The show's opening scene -- dubbed "Green and Pleasant," after a line from poet William Blake's "Jerusalem" -- will then unfurl, presenting an idyllic view of the British countryside.
The elaborate set will comprise rolling hills, fields and rivers, complete with picnicking families, sport being played on a village green and real farmyard animals.
These will include ducks, geese, 12 horses, three cows and 70 sheep, plus three sheepdogs to keep them in line.
The national flower of each of the four nations that make up the United Kingdom will also be represented -- the rose of England, the Scottish thistle, Welsh daffodil and flax from Northern Ireland -- organizers say.
In case the heavens don't open for real, Boyle has lined up fake clouds to shade his pastoral scene.
It's expected that three more set-pieces will follow, including a special sequence celebrating the "best of British," featuring volunteer performers from the NHS, or National Health Service.
Boyle and his technical crew will be holding their breath for it all to run smoothly -- not easy, given the cast of 10,000 adult volunteers and 900 local schoolchildren, not to mention a heavy-duty flying system, nearly 13,000 props and an array of technological wizardry.
Then will follow the traditional elements of the ceremony, as required under the International Olympic Committee charter, the organizers say.
The queen will be greeted at the entrance to the stadium by IOC president Jacques Rogge.
Then the athletes -- who, after all, are the real stars of the Olympic show -- enter the stadium, team by team in alphabetical order, apart from Greece, which enters first in recognition of its status as the birthplace of the Games, and Great Britain as the host nation, which enters last.
Each team delegation will be led in the parade by a visiting head of state or dignitary -- in the case of Team USA, by first lady Michelle Obama, who has said the honor "is truly a dream come true."
After speeches from Olympic officials -- including Sebastian Coe, head of the London organizing committee and himself a former gold medalist, the queen will declare the Games open and the Olympic flag will be hoisted above the stadium, to fly throughout the event.
A participating athlete, judge and coach from Britain will then take an oath vowing to compete and judge according to the rules of their respective sport, one hand holding the flag and the other held aloft.
The grand finale will see the Olympic torch enter the
stadium, the last stage in a 70-day, 8,000-mile relay around the United Kingdom, and set the Olympic cauldron aflame, symbolizing the beginning of the Games.
Who the final torchbearer will be has been the subject of much speculation, and perhaps the best-kept secret of all.
One name mentioned has been that of footballer David Beckham, who has a role at the ceremony, although he told CNN on Tuesday that the honor should go to someone who has competed at the Games.
Others suggest that an Olympic hero of past games, like rower Steve Redgrave or decathlete Daley Thompson, or a group of athletes could be involved -- or even that the queen or another royal might step up to the cauldron.
Whoever it turns out to be will have the eyes of the world upon them as they wrap up a spectacle that, in the words of Boyle, aims to "be as unpredictable and inventive as the British people."
CNN's Chris Murphy contributed to this report.