The app includes all of BT's channels: BT Sport 1, BT Sport 2, BT Sport 3, ESPN, Boxnation and BT Sport Extra. Video is available in HD to begin with, while the BT Sport 4K UHD channel will be added later this year along with HDR colour and contrast enhancements.
Also added later will be the ability to view on demand content from the broadcaster.
A BT Sport app subscription is available from £9 per month when taken with BT broadband. That's the only way to get it if you plan to solely watch through the TV app itself.
The other way is to subscribe through a paid TV service, such as Sky Q or TalkTalk TV. That costs £27.99 on top of a usual plan.
Virgin Media customers on Full House or VIP plans get BT Sport included, while those on Player or Mix bundles can get it for £18 extra.
EE customers on a Max plan can also get BT Sport access from £10 per month. They just need to text "Sport" to 150.
All existing BT Sport subscribers can simply use their existing log in on the new app. That means they can use the app for second screen viewing.