Beginning in Season 7, Cersei's costumes became darker, sleeker, and more modest. Symbolically representing armor, Clapton began fitting the current Queen of the Seven Kingdoms in heavy black materials with heavy military vibes but marrying them with dark fabrics to reflect the fact that Cersei was very much still in mourning.
Keeping her feud with Daenerys Targaryen in mind, Clapton designed a costume that encapsulated Cersei's hardened outlook during her temporary cease-fire meeting with the Mother of Dragons. While gathered around with other, less terrifying leaders of the realm to see proof the Army of the Dead was approaching, Cersei quite literally armored herself in a military inspired black dress, featuring structured shoulders, chainmail, and a "lizard-like" coat.
According to Clapton, the purposeful wardrobe change offered a subtle, yet significant tone as it "creates an illusion that you can see into [Cersei's] soul, and it’s dark."
