Within the competitive space of original programming, Starz has moved from an also-ran to a formidable player in just the last few years. Dramas like “Power” and “Outlander,” both of which premiered in 2014, have received good ratings and reviews. “The Girlfriend Experience,” a half-hour drama that debuted in April, was also warmly received by critics.

In mid-July, beginning with the third season of “Power,” Starz will premiere new episodes of original programming on Sunday nights, a sign of confidence in its lineup as it goes head-to-head against rivals like HBO and Showtime (the network had previously aired new episodes on Saturday nights). And like HBO and Showtime, Starz introduced a stand-alone app this year.

Starz’s resurgence has been led by Chris Albrecht, the former chief executive of HBO.

In a call with reporters on Thursday morning, Lionsgate’s chief executive, Jon Feltheimer, suggested that Mr. Albrecht would retain an important role in the combined company. “We expect Chris not only to continue to run Starz, but also to have a major participation and leadership of the entire combined company,” he said.

Earlier this week, Starz announced that Mr. Albrecht had renewed his contract to remain as chief executive through 2020.

Speculation about a combination of Lionsgate and Starz had been percolating, heating up early last year when Mr. Malone engineered a stock swap involving the two companies. But there were several complicating factors then, including the ownership percentages that Mr. Malone and Lionsgate’s biggest shareholder, the investor Mark Rachesky, would hold.