Comcast’s streaming service Peacock has managed to convince 15 million people to sign up since it launched nationally in July and exclusively to Comcast’s cable and Internet customers in April, the company’s chief executive said at an industry conference on Tuesday.

Speaking at the Goldman Sachs Communacopia conference, Comcast CEO Brian Roberts said the service has added 5 million more subscribers to Peacock compared to this time six weeks ago.

Peacock offers TV shows and movies from Comcast’s library of content across several brands, including NBC, Universal Pictures, NBC News, USA Networks, NBC Sports SyFy and Sky. The service has three subscription tiers: A free plan with a limited amount of movies and shows; an ad-supported, $5 a month version with an expanded amount of content and an ultra-premium, commercial-free version at $10 a month. Comcast’s cable and Internet customers get access to the middle tier for free and the higher tier at a discount rate.

Roberts didn’t break out which customers subscribe to which tier. But Peacock’s momentum puts it way ahead of rival AT&T service HBO Max, which has managed to land just 4 million subscribers since launching in May.

Like HBO Max, Peacock is unavailable to streaming households who use Roku or Amazon Fire devices because Comcast has been unable to settle on terms that would bring the service to those platforms. The Desk was the first to report in June that Peacock would skip Roku and Amazon Fire devices at launch.

Unlike HBO Max, Peacock is available natively to Comcast’s TV customers on the X1 platform and to Internet subscribers who obtained a free Flex set-top box from the company. Around 2 million Comcast Internet customers have a Flex box, Roberts said.

As of September, Peacock was the second-most streamed app on Flex boxes and the third-most used app on cable X1 boxes, coming behind YouTube on X1 and Netflix on both platforms, Roberts said.