Disney's ESPN has signed a deal with Activision Blizzard for live TV coverage of the Overwatch League, an esports league. The deal is the biggest yet for video game developer Blizzard Entertainment, and deepens ESPN's commitment to esports, where spectators watch professional video gamers compete.

The Grand Finals will mark the first broadcast of an esports championship on Disney's flagship TV network, ABC, and the first time live competitive gaming will air on ESPN in primetime.

Overwatch coverage will begin with the playoffs on July 11, across both Disney XD and ESPN networks and will finish with the Grand Finals live from Barclays Center in Brooklyn, New York, July 27–28. A recap of highlights will air on ABC on July 29. All coverage also will be available for ESPN and Disney network subscribers to stream live on the ESPN App and DisneyNOW.

As the popularity of eSports explodes, thanks partly to games like Fortnite and Dota, mainstream television networks have taken interest. Back in 2016, eSports had its first primetime moment when the CW partnered with digital network Machinima to bring its web docuseries "Chasing the Cup" to its digital platforms and broadcast television. ESPN has also been known to broadcast eSports and entered into several deals in recent years, notably FIFA 17 Ultimate Team Championship and Madden NFL 18 Championship Series, according to ESPN.

--CNBC's Julia Boorstin contributed to this report.