Game Of Thrones' Lena Headey wears a Run-DMC T-shirt as she and her boyfriend Marc Menchaca work out

'Game of Thrones' Prequel Series 'Tales of Dunk and Egg' in Development at HBO

Game of Thrones' prequel Tales of Dunk and Egg 'is in early development' at HBO

Lena Headey cools off in bra top and leggings after working out with beau Marc Menchaca in Hollywood