T-Mobile US is reportedly working with Facebook to add the social network giant to the growing list of content partners on Binge On, the operator’s zero-rated video streaming service.

According to Re/code, the two companies have been collaborating to add Facebook video to the list of services that T-Mobile US supports for some time, with work still ongoing.

T-Mobile US announced new partners had joined the service last month, naming 12 additions, giving it more than 80 in total.

A host of big names are now using the service, which allows T-Mobile US customers to stream its partners’ video without eating into their data allowance, albeit at a lower quality,  including NBC, HBO and ESPN.

Google’s YouTube was also added in March, leaving Facebook and Snapchat as two notable exceptions.

The US operator has consistently maintained it is open to providing access to Binge On for all interested parties, since its launch last November, but technical work is required to ensure the video stream is identified to T-Mobile US’ network, added the Re/code report.

Binge On, after initially courting controversy in the industry for supposedly going against net neutrality principles, has been a success according to T-Mobile US figures, which claimed in May customers have streamed more 377 million hours of video since its launch.

Consumers viewed up to 2x more content from providers using Binge On.

For Facebook, which is stepping up its efforts in video, this could be vital in encouraging its users to watch more content on the platform.

The report added that T-Mobile and Facebook are also looking into whether they could bring the social network’s Free Basics initiative to the US.

Free Basics has been rolled out by Facebook in emerging markets to provide select parts of populations with access to select internet services for free. However, the service was effectively banned in India earlier this year, following an intense debate.