Gormley says he wants some "ordinary people" to take part
Hundreds of people will get the chance to become a work of art on Trafalgar Square's fourth plinth later this year.
More than 2,400 people are needed to stand on the plinth over 100 days as part of Antony Gormley's living artwork, The One and Other.
Gormley said he hoped the whole of the UK would be represented.
He said: "It is about putting the living body in place of a statue and learning how people feel being that alone in such a public place."
The One and Other will see volunteers occupy the plinth for one hour at a time later this year.
Turner Prize-winner Gormley announced the registration process in central London.
What would you do on the plinth?
He told the BBC: "Trafalgar Square is a good place to choose to think about making a portrait of the UK now.
"The idea is to use those few square meters of the plinth for the people of Britain to come here, and stand for an hour at a time, and be themselves for everybody.
"I think of it as a monument made in time to give us a sense - through those 2,400 hours - of what people really care about, what their hopes and fears are about living now."
Gormley, who is best known for the Angel of the North, said the 2,400 hours would be carved up to make sure that all walks of life were represented - but participants would be chosen at random.
He said he expected exhibitionists and members of pressure groups to apply, but added that he hoped they would be joined by "ordinary people".
Gormley said: "It is important we don't see this in terms of simply making a spectacle in the manner of a populist version of David Blaine.
"Turn that around and think of it from the point of view of the subject. What do you learn about the world from looking at it from this elevated and central position? What do you think about your life in this hour? That's what I'm interested in."
Gormley won the opportunity to showcase The One and Other last year, along with artist Yinka Shonibare's Nelson's Ship in a Bottle.
They beat four other contenders to the honour, and will take turns to replace Thomas Schutte's Model for a Hotel 2007 which occupied the plinth for more than 18 months.
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