LONDON — U.K. pay TV operator BSkyB and HBO are to co-develop and produce original drama series as part of an expanded partnership between the two companies. The shows will be “epic drama of a truly spectacular scale,” Jeremy Darroch, BSkyB’s chief executive, said.

The pair has reupped their output deal to ensure that BSkyB’s premium channel Sky Atlantic remains the exclusive home of first-run HBO shows in Britain and Ireland through 2020.

BSkyB and HBO will work together to develop and produce upscale drama series with the potential to run for multiple seasons and to commission these shows, with production to be jointly funded by the two companies.

The co-production pact builds on the deal that BSkyB and HBO inked in 2010, when Sky Atlantic launched.

With the extended output deal, new HBO shows — including “True Detective” and “Looking” — will continue to premiere exclusively on Sky Atlantic, along with the return of shows such as “Game of Thrones,” “Boardwalk Empire” and “Girls.”

In addition to linear broadcast, the output deal covers a broad range of multiplatform rights, ensuring HBO content will continue to be available live and on demand not just on TV, but online and on mobile through Sky Go. Sky Atlantic is also available live and on demand through NOW TV, Sky’s new internet TV service.

Jeremy Darroch, BSkyB’s chief executive, commented: “HBO is synonymous with must-see TV that pushes creative boundaries, so it’s no wonder that Sky Atlantic is such a hit with our customers. By expanding our relationship with HBO, we are strengthening our commitment to bring customers the very best content from around the world.

“Original production is the natural next step for our partnership with HBO and we are enormously excited at the prospect of working together to realize our shared vision for epic drama of a truly spectacular scale.”