Antony Gormley says he hopes "everyone" will apply to take part
The search has begun for members of the public to become living works of art on Trafalgar Square's fourth plinth.
Artist Antony Gormley wants more than 2,400 people to stand on the central London plinth for one hour each, over 100 days from 6 July.
He has invited volunteers to register via the website www.oneandother.co.uk, with participants selected at random.
However Westminster City Council warned that it had yet to grant planning permission for the project.
Mr Gormley, who created the Angel of the North, said he hoped the whole of the UK would be represented in the work, entitled One and Other.
Volunteers would be free to do whatever they liked on the plinth, as long as it was legal, and Mr Gormley said he expected some people to behave quite outrageously.
This is the real beginning of the project when it starts to get exciting
The different regions of the UK would be represented proportionally, including 304 participants from London.
Mr Gormley said the work would be "about putting the living body in place of a statue and learning how people feel being that alone in such a public place".
It is proposed that events on the plinth would also be streamed live on the internet.
The artist added: "This is the real beginning of the project when it starts to get exciting. I hope that everyone will apply."
London Mayor Boris Johnson also urged people to sign up.
"The One and Other is an opportunity to turn yourself into a work of art and create something unprecedented and inimitable in this wonderful city of ours," he said.
Westminster City Council's head of development planning services, John Walker, said it had only recently received the project's planning application.
The council's planning committee will consult upon it before granting permission, he added.
"It is not a straightforward case because, in addition to the artwork itself, there is a lot of supporting infrastructure needed to run the event and this will take up a significant amount of space in the square," Mr Walker said.
"We have serious concerns that the organisers are encouraging people to apply to take part when, like any other planning application, it needs to be properly considered."
Trafalgar Square's fourth plinth has been reserved for work by contemporary artists and has previously displayed art by Thomas Schutte and Marc Quinn.