How do I add Comcast as my TV Provider for Single Sign-On on my iPhone?

iOS 10.2 includes a Single Sign-On feature which allows pay-TV users to sign-in to specific apps just once across all their Apple devices. iOS users can sign-in to their cable or digital TV provider by navigating to Settings > TV Provider on their iPhone or iPad. As of right now (iOS 10.2 beta 5) the list only includes: CantruyLink Prism, DIRECTV, Dish, GTA, Hawaiian Telcom, Hotwire, MetroCast and Sling TV. While it is safe to assume Apple plans to add more providers in the future, one major cable company has opted not to support Apple’s SSO feature.