The Disney boss' biggest acquisition ever, valued at $52.4 billion, is set to create a global content powerhouse.

Now it's official. The Walt Disney Co. has agreed to acquire big parts of 21st Century Fox in an all-stock deal worth $52.4 billion, or approximately $66.1 billion when including debt, valuing shares of Fox at around $40 apiece while they had traded Wednesday at $32.75.

In another key news update, Disney said that longtime boss Bob Iger has extended his contract as chairman and CEO through the end of 2021.

The acquisition is expected to yield "at least" $2 billion in cost savings "from efficiencies realized through the combination of businesses, and to be accretive to earnings before the impact of purchase accounting for the second fiscal year after the close of the transaction," Disney said.

Asked about opportunities to boost revenue with the deal, Iger said on a call that "we are not getting specific on that," but said using more intellectual property will be a key focus here. Management said the full financial benefits of the deal would become visible by 2021.

The companies are preparing for an extended regulatory review and closing process, with Disney CFO Christine McCarthy on a conference call saying the closing is expected to take 12-18 months.

"The boards of directors of Disney and 21st Century Fox have approved the transaction, which is subject to shareholder approval by 21st Century Fox and Disney shareholders, clearance under the Hart-Scott-Rodino Antitrust Improvements Act, a number of other non-United States merger and other regulatory reviews, and other customary closing conditions," they said.

Fox's stock had traded at $25 a month ago, before it was reported the two conglomerates were close to a transaction.

The deal, which has been in the works for weeks and was confirmed early Thursday, will see Disney buying Fox's film and TV studio, the National Geographic and FX cable channels business, regional sports networks, international networks, including Star India, Fox's 30 percent stake in Hulu and its 39 percent stake in European pay TV giant Sky.

Immediately prior to the acquisition, Fox will separate the Fox Broadcasting network and stations, Fox News Channel, Fox Business Network, FS1, FS2 and Big Ten Network into a newly listed company that will be spun off to its shareholders.

The 53-acre Fox studio lot on Pico Boulevard near Los Angeles will stay with that company that will remain under the control of Rupert Murdoch, though it remains to be seen what the plans are for the $425 million piece of property.