Slideshow ( 2 images )

(Reuters) - CBS Corp CBS.N and Viacom Inc VIAB.O agreed to merge on Tuesday, creating a company with more than $28 billion in revenue, as an increasingly competitive media landscape prompted their controlling shareholder to reunify the U.S. entertainment companies 13 years after breaking them up.

Each Viacom Class A voting share and Viacom Class B non-voting share will convert into 0.59625 of a Class A voting share and Class B non-voting share of CBS, respectively, the companies said.

The two companies are controlled by National Amusements Inc, the holding company owned by billionaire Sumner Redstone and his family.