It is billed as the world's most lavish student crash pad - a stunning penthouse with panoramic views of Central Park that smashed records as New York's priciest property when it sold for $US88 million ($85 million) in February.
The palatial apartment atop one of Manhattan's most prestigious buildings was bought for Ekaterina Rybolovleva by a trust funded by her father, Dmitry, a billionaire Russian oligarch who made his fortune from fertiliser and became known as the "potash king".
Miss Rybolovleva, 22, a Monaco resident and keen horsewoman, is said to be intending to use the 6744 square feet apartment during trips to New York when she takes a course this autumn 200 miles (322 kilometres) away at Harvard.
The penthouse at 15 Central Park West - a New York landmark in which neighbours include Sting, the pop star, and Denzel Washington, the actor - is believed to be the world's most expensive property in terms of price per square foot.
It has a main bedroom shaped elliptically to maximise the views, skylit gallery, chef's kitchen, library with a wood-burning fireplace, a study panelled in Brazilian rosewood, 17 wardrobes and a 2100 square feet terrace that wraps around three sides of the building.
You could fit her whole class in there. Imagine the student parties
But now a lawsuit filed by Mr Rybolovlev's estranged wife, Elena, claims that the tycoon, whose estimated worth is $US9 billion, splashed out on the penthouse as part of a concerted international effort to hide his assets during their protracted and bitter divorce.
The apartment was bought by a private company held by a trust operating independently of Mr Rybolovlev, 45, for the benefit of his oldest daughter, according to Tetiana Bersheda, a lawyer for the tycoon.
But Mrs Rybolovleva, 45, contends in papers filed in New York state supreme court that, in reality, her husband bought the property through a "sham entity" in breach of a Swiss court order freezing his assets.
"It's a joke to claim that he spent $US88 million on such a huge apartment so that his daughter can supposedly use it on occasional visits to the city when she is not even studying here," said her lawyer, David Newman. "You could fit her whole class in there. Imagine the student parties."
The showdown over the apartment is the latest stage in the rancorous and expensive split of a couple who enjoyed a rags-to-riches story after the collapse of Communism.
They barely had a rouble to their name when they met on their first day at college in the industrial Russian city of Perm in the 1980s. Now they are wrangling over trophy homes across Europe, two empty American properties that cost $US183 million, a $US100 million yacht, a private jet and an estimated $US1 billion furniture and art collection.
In a divorce petition filed in December 2008, Mrs Rybolovleva claims that her husband's philandering became increasingly regular, often involving parties on a yacht named after Anna, their second daughter born in 2000.
The fallout has been spectacularly ugly. Last year, Mrs Rybolovleva reportedly rejected an $US800 million settlement that would have represented less than 10 per cent of his estimated worth.
The final deal seems certain to be the costliest divorce in history.
The Sunday Telegraph, London