The Walt Disney Co. has agreed to a $US52.4 billion ($A73.4 billion), all-stock deal to acquire 21st Century Fox and other entertainment and sports assets from Rupert Murdoch’s empire.

The deal between Disney and 21st Century Fox marks a historic union of Hollywood heavyweights and a bid by Disney to bolster its core TV and film businesses against an onslaught of new competitors in the content arena.

The transaction unveiled early on Thursday morning has a total value of $US66.1 billion, with Disney assuming $US13.7 billion in 21st Century Fox debt.

Disney is buying a large part of the Murdoch family’s 21st Century Fox in a $US52.4 billion deal, including film and television studios, cable and international TV businesses as it tries to meet competition from technology companies in the entertainment business.

Before the buyout, 21st Century 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.

Fox assets that will be sold to Disney, include the Twentieth Century Fox movie and cable networks.

Fox currently owns the rights to the X-Men and the Fantastic Four and has had mixed success with both.

Under the mega-merger, Marvel – which is owned by Disney – will regain the rights to two of its biggest properties from the comic books.

Disney will also assume about $US13.7 billion of net debt of 21st Century Fox.

Disney Chief Executive Bob Iger, 66, will extend his tenure through the end of 2021 to oversee the integration of the Fox businesses.

He has already postponed his retirement from Disney three times. In March, he said he was committed to leaving the company in July 2019.

The entertainment business is going through big changes with tech companies building video divisions and advertisers following consumer attention to the internet.

Disney is launching new streaming services, which could be helped with the addition of the Fox assets.

Having its own services will allow Disney to bypass the likes of Netflix and charge consumers directly for access to its massive content library.

-with AAP and ABC