Because the Empress never stands up in the scene, it’s not clear whether the circular piece behind her head is part of her costume or part of the chair. Well, it’ is actually a costume piece…that’s been repurposed as the backrest of the throne.
The piece is the back side of the original cape with a silver foil disc that Ginger wore to the VIS party. There’s a good view of it from the Salmagundi party pictures.
In the film, Ginger’s costume is updated to a darker gown, and with a shoulder piece similar to the Space Force collars. The corners are decorated with rings of green hair matching her headpiece. The metal “breasts” from the original costume are retained.
It’s really a rich and luxurious scene made from almost literally nothing.