The billionaire James Packer and his wife, Erica, are understood to have spent $18 million on their first family property.
But neighbours do not expect them to be moving in until they demolish and rebuild the hillside Vaucluse holding.
Their disguised purchase was fronted by Matthew Csidei, a former housemate of Mr Packer, in an attempt to keep the vendor's price expectations as low as possible.
It was listed with $17 million-plus hopes through the agents Bill Bridges and Craig Pontey by the executors of the estate of the oil shale pioneer Sir Ian McFarlane, who died last year.
It comes with 2374 square metres of land - plenty of space for the Packers' 10-month-old daughter, Indigo, to enjoy a backyard away from the paparazzi.
The sale scuttles the entrepreneur Deke Miskin's hope that the Packers would buy the Point Piper harbourfront home Altona, in a deal where Mr Miskin would have secured Mr Packer's redundant Bondi Beach complex.
But there is still speculation that the Packers, who married in June 2007, may yet expand their Bellevue Hill holdings with the purchase of the 1890 property Leura, listed for $50 million.
Leura sits between Cairnton, Mr Packer's mother Roslyn's residence, and Winston, his sister, Gretel's house.
Any demolition of the Vaucluse house may cause controversy, as it is a landmark Guilford Bell house designed in the early 1970s for McFarlane.
Its proposed heritage listing by Woollahra Council was successfully opposed by McFarlane's solicitor, Robert Minter, in 2006.
McFarlane's valuer said heritage listing would diminish the property's value by $4 million, as the house's colonnade was an example of a style that was no longer popular. (Credit: The Sydney Morning Herald)