The hotel famously called "the greatest of them all" is now the most expensive of them all.

Hilton Worldwide Holdings said it's selling the famed Waldorf Astoria hotel in New York for $1.95 billion to China-based buyer Anbang Insurance Group.

The price makes the Waldorf the most expensive single hotel ever sold in the U.S., according to Daniel Lesser, CEO of LW Hospitality Advisors, which counsels the hotel industry.

Until the sale, the most expensive single-hotel deal was believed to be the sale of The Cosmopolitan hotel and casino in Las Vegas to Blackstone for $1.73 billion, but that transaction also included the casino.

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"This is the largest single-hotel transaction period," he said. "Certainly in the U.S., and maybe for the world."

By comparison, a controlling stake in New York's other iconic hotel—the Plaza—sold for $570 million in 2012, though that building is again for sale.

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Lesser said the Waldorf deal works out to about $1.4 million per room key.