The hotel has been bought by Abu Dhabi based Twenty14 Holdings, the hospitality investment arm of LuLu Group International.
Twenty14 Holdings, founded in 2014 to capitalise on the growth in the global hospitality industry, plans to add a further 50 rooms to the 241-room hotel, in a £20m refurbishment.
Managing director Adeeb Ahamed said: "We are excited to add The Caledonian to the portfolio of Twenty14 Holdings. With more than hundred years of history, The Caledonian brings with it a rich heritage, character and unique opulence.
"We are honoured to be part of this Scottish landmark that has a great connect with the locals and visitors alike. We look forward to adding to the experience The Caledonian already offers."
Ahamed said an upgrade to F&B facilities is also under consideration at the hotel, which will continue to be operated by Waldorf Astoria.
Investment firm Twenty14 Holdings currently has assets worth more than $650m (£473m), including 1-5 Great Scotland Yard, London, the former headquarters of the Metropolitan Police, which it purchased for £110m and plans to convert into a five-star hotel.
Commenting on the sale, Will Duffey, co-head of European transactions for JLL's hotels & hospitality group - who oversaw the sale with HVS Hodges Ward Elliott, said: "The hotel has long been seen as a jewel in the crown of the UK hotel market.
"Our client's recent refurbishment programme repositioned the hotel to its former glory when it reopened as the first Waldorf Astoria in the UK in 2012.
"We are delighted to have advised on this irreplaceable trophy hotel overlooking Edinburgh Castle to an investor who will preserve and protect this most important of assets for generations to come."
The Waldorf Astoria Edinburgh was built in 1903 and underwent a £24m renovation before relaunching in 2012.
It was constructed by the Caledonian Railway Company within the tradition of grand railway hotels.
Former guests include Charlie Chaplin, Laurel and Hardy, Elizabeth Taylor and America's 44th President, Barack Obama.
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