AT&T will make a run at Netflix with a new streaming service that'll feature HBO and other media properties acquired in the Time Warner merger.

The unnamed streaming service will launch next year in the fourth quarter, WarnerMedia CEO John Stankey said on Wednesday. "This is another benefit of the AT&T/Time Warner merger, and we are committed to launching a compelling and competitive product," he said in a statement.

The new service will be anchored by HBO as the lead brand, but also host films and TV franchises from WarnerMedia, which owns Warner Bros., Stankey told CNBC in a taped appearance. So far, AT&T is remaining mum on pricing, but Stankey said it'll be more expensive than WarnerMedia's existing HBO Now streaming service, which goes for $15 a month.

"You can buy HBO separately, and that will still continue to be the case," he added.

In his statement, Stankey signaled that he wants third-party titles on the platform, too. "We expect to create such a compelling product that it will help distributors increase consumer penetration of their current packages and help us successfully reach more customers," he said in his statement.

When the service goes live, it'll face some stiff competition. Disney is also preparing to launch its own streaming service, which is reportedly set to arrive in fall 2019. Meanwhile, Netflix continues to add millions of new subscribers each quarter and has budgeted about $8 billion this year for new content.

To compete, Stankey said back in June he was going to boost funding to HBO's original-programming budget, some of which will go toward a new Game of Thrones spin-off series. Company subsidiary Warner Bros. also recently launched a $7.99-a-month comic-related streaming service called DC Universe.

Why doesn't AT&T simply funnel more money into HBO's existing streaming service? Stankey told CNBC the HBO brand offers a particular type of content. "This is a new bundle. It's a way to think about a bundle… and how to get the right brands together in an on-demand world."

Right after the Time Warner merger, AT&T launched a separate streaming service called WatchTV, which is designed for smartphone users and features over 30 live channels. It costs $15 per month as a standalone service.