It is well known that Lena Headey and Jerome Flynn refused to work with each during Game of Thrones filming because they had a messy breakup.
It is now known that it was Lena SPECIFICALLY who made the request to never work with him, a new source who worked on the show said:
“Lena and Jerome have not filmed together due to a bad break-up.
“They kept the full extent of it secret but it was a very turbulent relationship and it has been very awkward on set.”
“Lena has opened up to her trusted friends. She appears to have a genuine hate towards him.”