Christo once wrapped up the Reichstag, suspended a curtain across a Colorado valley and covered up the Pont Neuf in Paris. Now, six years after the artist’s death, a London gallery is to create a monumental installation he designed in 1968, using a detailed scale model and drawings that had been presumed lost until their chance discovery.

Christo had imagined a vast, internally illuminated suspended form, like a cloud, but technical constraints meant the plan was never brought to fruition.

Package on a Ceiling was conceived for the Institute of Contemporary Art in Philadelphia. Now its first realisation will fill a huge exhibition space at Gagosian London in a collaboration with the Christo and Jeanne-Claude Foundation.

The piece will fill the full volume of the space – 16 metres long, 10 metres wide – descending to just above head height.

Serena Cattaneo Adorno, a senior director at Gagosian, said: “Both architectural and atmospheric, it compels visitors to move beneath and around it.”

She added: “This exhibition brings a work into being that has existed for decades only as an idea. The gesture of wrapping is one of the most radical aspects of Christo and Jeanne-Claude’s practice; here, it is applied to air and architectural surface – a distillation of their thinking to its purest form.”

The original plans were discovered by Lorenza Giovanelli, who joined Christo’s team in 2017 as his studio manager. While creating more space within the busy studio, she moved a large plinth and suddenly noticed a box within its hollow. To her astonishment, it contained a detailed scale model of Package on a Ceiling, mocked up in a gallery maquette complete with electrical wiring to convey the work’s lighting elements.

Its discovery in 2018 was never revealed, and Christo died in 2020. She recalled his excitement as he had long ago forgotten placing it in that plinth and had moved on to other works. She said: “It’s in such great condition because it’s never seen the sunlight. It was not even dusty … It’s been hidden for 50 years.”

She said: “It will look like a beautiful cloud, lit from within, hanging from the ceiling of the gallery space … It will be very magical … I’ve imagined this many times. So I am really impatient to see it.

“I believe people will really find it extremely beautiful.”

Christo and his wife, Jeanne-Claude, are best known for monumental, temporary public artworks that transformed landscapes using everyday materials. Such was the complexity of their projects that they involved years of planning yet existed only briefly before being dismantled and recycled.

It was in the 1960s that Christo explored the concept of wrapping air, sealed within transparent polyethylene packages bound with rope. It foreshadowed later works at an environmental scale.

The Gagosian exhibition will include various works on the theme of air – “invisible, intangible and essential”. Giovanelli said of the artist: “He was full of ideas, full of energy, full of life … He was never too much concerned about people not understanding the work. He was happy that people would get curious to see the work one way or the other. He always said that the most important thing in life is to be curious.”

Vladimir Yavachev, Christo’s nephew, who worked closely with the artist in his lifetime, said of the Package on a Ceiling plans: “They’re very precise drawings … and the scale model has all the information in it … You can look at every detail. It’s there.”

He added that, in making it look just like those drawings, they would have recreated Christo’s vision.

• The exhibition will run from 21 May to 21 August at Gagosian London, 20 Grosvenor Hill, W1