** Spoiler Alert **
First evidence comes from a 2 month old Reddit post when a fan noticed Aisling Franciosi (Lyanna Stark) following Scolding on Twitter and Scolding following official Game of Thrones twitter handle and Liam Cunningham (Davos):
Major Spoilers Below
Second evidence- The recent HBO hack has led to the leaking of a confidential document which puts Scolding’s name on Game of Thrones’ season 7 casting list. Also, the plot leaks floating around on social media have claimed that there will be a flashback scene involving Rhaegar Targaryen and so far those leaks have come true.