These pictures show similar artists to Katy Perry (Shontelle and Eliza Doolittle) wearing an over sized t-shirt - in the top photo. Followed by the high-top trainers in the second photograph. These are some brief ideas for the costume of the actress who will be playing Katy Perry. High-tops trainers and over sized t-shirts will represent a tom-boy but in a sexy, stylish way which fits into the image of Katy Perry. We would use this outfit look, for a main performance aspect of the video.