Walt Disney Co. agreed Thursday to buy key film and television assets of 21st Century Fox, in a $52.4 billion deal set to reshape the entertainment landscape and step up a challenge to Netflix and emerging rivals in the streaming wars.

The blockbuster stock transaction also vastly reduces the Fox media empire built by Rupert Murdoch, leaving the 86-year-old tycoon and his two sons with a more tightly focused group including the Fox broadcast network, Fox News Channel and sports channels.

The deal will see Disney acquire the vaunted Fox Hollywood film and television studios, cable entertainment networks and international TV businesses, bringing popular entertainment properties including "X-Men," "Avatar," "The Simpsons," FX Networks and National Geographic into Disney's portfolio.

"The acquisition of this stellar collection of businesses from 21st Century Fox reflects the increasing consumer demand for a rich diversity of entertainment experiences that are more compelling, accessible and convenient than ever before," said Disney chief executive Robert Iger in a statement.