Katy was spotted promoting her new novel “Sapphire” at Selfridges in London with her boobs popping out.

The model/author looked sexy in a light blue sequined leotard as she posed for the paparazzi among blue-brief-clad chiseled male models, who all had “Sapphire” branded on their torsos.

Katie was surrounded with hunks as she poses for photos holding a copy of her novel.