Single Sign-On, a feature that remembers and uses your cable/satellite logins across compatible video apps for the iPhone, iPad, iPod touch and Apple TV, was originally promised months ago and should finally go live alongside public releases of iOS 10.2 and tvOS 10.1 next month.
As noted by MacRumors, AT&T's DirecTV service is now being listed as a Single Sign-On compatible app alongside the previously listed compatible providers: Dish, Sling TV, Hotwire and GVTC Communications.