There will be "misbehaving corgis", a giant puppet dragon and the Queen’s image flying high above the crowd on a giant helium balloon.
The Platinum Jubilee street pageant will be a "sensory explosion" of colour and carnival, music and theatre, organisers have said, describing it as "one of the most ambitious events that Britain has ever staged".
The pageant will be on a vast scale, involving more than 5,000 people, and will take place on Sunday, June 5 next year, bringing an energetic and dramatic end to a four-day Bank Holiday weekend.
Senior members of the Royal Family including the Queen, the Prince of Wales and the Duke and Duchess of Cambridge are expected to take part in the opening procession before watching the rest of the event from a viewing platform.
It is hoped that the finale will also incorporate a Buckingham Palace balcony appearance featuring the wider family, including Prince George, seven, Princess Charlotte, six and Prince Louis, three.
Nicholas Coleridge, the co-chairman of the organising committee, said it would be the nation’s "biggest celebratory event on the nation’s greatest street [The Mall] for a long, long time".
The Platinum Jubilee street pageant will be a 'sensory explosion' of colour and carnival, music and theatre, organisers say
"The Platinum Jubilee weekend is an opportunity for the country to emerge, re-energised and renewed, expressing optimism and confidence," he added.
"It will be something of a reopening ceremony for the United Kingdom following a period of uncertainty and hardship – a catalysing moment of unity and fun."
The pageant will tell the story of the Queen’s seven decades on the throne, celebrating her service and passions from racehorses and corgis to the Commonwealth and the environment.
It will recognise the achievements and progress since the dawn of the second Elizabethan age, showcasing the transformation of society and changing tastes in fashion, culture, music and sport from the 1950s to the present day.
The seven "chapters" will incorporate the constant yet evolving presence of the sovereign, organisers said, and will be told by a variety of artists and communities.
The carnival will be based on a mythical story called There Once is a Queen, written by Sir Michael Morpurgo, the author of War Horse, which will be brought to life by the pageant master Adrian Evans.
The pageant will play out over three acts – ceremonial, celebratory and finale. It will be funded by private partnerships to the tune of between £10 million and £15 million.
The opening, ceremonial section will feature marching bands, serving troops and others marching through central London. The organisers said it had been designed to showcase the military precision and ceremony for which the UK is famous.
The celebratory section will open with "monumental, heraldic figures" to remind the nation of a royal lineage stretching back more than 1,000 years.
Among them will be a puppet dragons larger than a double decker bus, with a wingspan the width of the Mall. A young Princess Elizabeth will be depicted teasing the dragon with a pearl, the traditional symbol of strength, wisdom and power.
The pageant will feature 'monumental, heraldic figures' including puppet dragons larger than a double-decker bus
The Coronation will be interpreted in carnival style, with the Queen and Prince Philip at its centre, while the couple’s presence in Kenya when George VI died in 1952 will be depicted via the imagined response of 250 safari animals.
There will be a river of flags designed by children from schools across the Commonwealth, a giant platinum crown, percussion bands, dancers and trapeze artists, while ponies, racehorses and misbehaving corgis "create comic chaos" across the Mall.
Royal weddings and jubilees will also be depicted, as well as the Queen’s care for local communities, nurturing of charities and love of the natural environment, which will be symbolised by an oak tree.
The late Duke of Edinburgh will be a "constant presence throughout", with one section dedicated to the imagined relationship of the Queen and the Duke behind closed doors.
The pageant will tell a "spectacular, unfolding story, filled with wonder, warmth, wit and wow factor," said Mr Evans.
"We expect a joyous atmosphere, a bobbing sea of Union Jacks and rousing cheers as hundreds of thousands of people come together to witness this moment in history," he added.
The finale, for now, remains shrouded in secrecy, with further details to be released next year.