It's a costly way to get your head in the clouds but Australia's most expensive apartment has been sold in Melbourne for a whopping $25 million.

The 750-square metre penthouse isn’t even built yet but will boast a 360-degree view of the city and sit high above the clouds on level 98 of the Australia 108 tower on City Road.

It’s been purchased by an unknown international businessman based in China who plans to live in the luxury pad when it’s completed in 2019.

The asking price works out at $33,000 a square metre.

Work on the site recently began with the demolition of the former building.

The skyscraper will be constructed in three phases.

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