MGM is about to become the sole owner of Epix with a deal to buy the stakes held by Viacom’s Paramount and Lionsgate that values the joint venture at $1.28 billion.

MGM agreed to pay $1.03 billion for Viacom’s 49.8% interest and Lionsgate’s 31.2% of the premium network business. The partners expect the deal to close this month, following approval by antitrust officials.

MGM chief Gary Barber says that Viacom and Lionsgate committed “to provide their theatrical releases for years to come.”

A break up of the joint venture appeared to be virtually inevitable since June when Lionsgate agreed to pay $4.4 billion for Starz, a transaction that closed in December. Lionsgate CEO Jon Feltheimer joshed with shareholders, at an Investor Day gathering in January, that “we will treat Starz just like any other third party customer that we paid $4 billion for.”

He says today that Lionsgate is “shifting our investment focus to our wholly-owned platforms,” but wishes MGM “great success in continuing Epix’s strong growth in the future.”

In addition, Viacom is eager to raise cash to reduce its debt. CEO Bob Bakish, who took the top job in December, has said that he planned to sell unnamed non-strategic assets.

Bakish says today that he welcomes “the opportunity to strengthen our balance sheet by realizing the value of our equity investment, while also extending the successful commercial partnership between Epix and Paramount Pictures with a new multi-year output agreement.”

Barber says that Epix will provide his privately held studio with “increased revenue diversity, new opportunities for growth, and earnings accretion for the benefit of stockholders.”

Epix CEO Mark Greenberg will stay with the company at MGM, but he and Epix will remain based in New York.

He tells us that Lionsgate and Viacom will continue to provide theatrical movies to Epix on an exclusive basis “well into the next decade.”

Greenberg adds that having a single owner also could “simplify our message” to the two largest distributors — AT&T’s DirecTV and Comcast — which do not offer Epix. It’s carried on Charter, Dish Network, Cox, and Verizon FiOS systems.

The change could make it easier for MGM to secure international rights for Epix and its productions.

Although Epix will continue to feature theatrical films, “we’ll explore new things and look more aggressively to expand the pie,” Greenberg says.

LionTree Advisors provided financial advice to Viacom and Lionsgate. Latham & Watkins handled legal matters for MGM with Shearman & Sterling doing the same for Viacom and O’Melveny & Myers doing so for Lionsgate.