(Reuters) - Next week, when WarnerMedia reveals details about its upcoming subscription streaming video service HBO Max, some current HBO subscribers in the United States will learn that they will have access to the new service at no additional charge.

FILE PHOTO: The logo for HBO is pictured during the HBO presentation at the cable portion of the Television Critics Association Summer press tour in Beverly Hills, California August 1, 2012. REUTERS/Fred Prouser/File Photo

These 10 million customers who have subscribed to HBO through an AT&T Inc T.N product will likely be grandfathered into HBO's current price of $14.99 for the foreseeable future, a spokesman told Reuters.

WHO IS ELIGIBLE?

If you have subscribed to HBO through an AT&T-owned product such as satellite TV provider DirecTV or AT&T TV Now streaming video service, you are eligible to access HBO Max at no additional cost.

AT&T Wireless customers on some unlimited data plans are also eligible to get HBO Max for free.

HBO Now customers who subscribed directly through WarnerMedia are also eligible.

WHO IS NOT CURRENTLY ELIGIBLE?

Current HBO Now customers who have subscribed through other services such as Amazon.com Inc AMZN.O or Apple Inc AAPL.O may not be eligible at launch.

HBO subscribers who have signed up through other pay TV operators such as Comcast Corp CMCSA.O or Cox may also not be eligible at the start.

WarnerMedia executives are currently negotiating with distributors that AT&T does not own in order to work out a way to offer HBO Max. It is not immediately clear if it will cost more than what HBO currently charges. This will affect about 25 million current HBO subscribers in the United States.