The new 'Game of Thrones' stage play 'The Mad King' has explicitly revealed that Lyanna Stark possessed the supernatural abilities of a greenseer and warg, apparently settling one of Westeros' longest-running fan theories.
The Royal Shakespeare Company's production, written by Duncan Macmillan with George R.R. Martin's involvement, explores the events surrounding the Tourney at Harrenhal and the beginning of Robert's Rebellion.