The Danish-Icelandic artist, whose iconic domestic projects include the 'Your rainbow panorama' at the ARoS Aarhus Art Museum and Copenhagen's recently-opened Cirkelbroen, said on Monday he wanted to "make dreams come true" with his latest project in France.
He plans to follow Anish Kapoor's controversial "Queen's vagina" sculpture at the Palace of Versailles outside Paris with "an incredibly high" fountain in its gardens.
But he refused to saw how big the jet of water which will be shot from the top of the crane in the Grand Canal would be, telling AFP cryptically that the "size is decided by the confidence in the more cosmic Baroque".
"Of course I could tell you how many metres it is, but I am not going to because we need to leave it to the audience to make up their minds how high is high," he said.
An enormous fountain did feature in the original plans for the baroque 17th-century palace drawn up by the "Sun King" Louis XIV's architect Andre Le Notre, but was never realised despite attempts to pump water over a hill from the mighty river Seine.
"We are going to make the impossible possible," the artist declared, "to make dreams come true."
Eliasson, 49, conceded that he was "behaving like a small arrogant king" by not revealing the enormity of his creation but said "aesthetic and cultural muscle" was not decided by size alone.
Nonetheless, he said he had designed it to be viewed from Versailles' Hall of Mirrors and from the "terrace in front of the palace, where it will be beautifully tall and well proportioned to the horizon.
"And when you walk down to the Fountain of Apollo it will be incredibly high," he added.
The artist is also transforming two groves or "bosquets" in the palace's gigantic gardens, creating an enchanted fog in one which he hopes the public will feel free to "fool around" inside.
"The circular curtain of mist [in the Bosquet de l'Etoile] offers the opportunity to run around and to become a fool... it is a true folly," he said.
While on windy days it "might barely be there... on a sunny day there might be rainbows" which would allow people to behave like "butterflies" he said.
The artist argued that turning "cultural institutions into places where people can meet and argue" was crucial to real citizenship, particularly in places such as Versailles, which symbolised France's absolute monarchy.
Eliasson roamed around the palace in the dark at night to get a feel for it, he said, going through secret doors and down hidden corridors.
He said he was also creating installations for inside the palace, some of which are so subtle that they may not be noticed by some of the one million visitors likely to pour through the palace over the summer.
Eliasson, who grew up partly in Iceland, will also decorate the Colonnade Grove with the dust left by a melting Greenland glacier that also featured in an installation he made in Copenhagen in 2014 and repeated for the COP21 climate change conference in Paris earlier this year.
His Versailles works will go on show from June 7th to October 30th.
Eliasson has previously wowed New Yorkers with his 10-storey urban waterfalls and Londoners with his giant trippy sunset at Tate Modern.