Katy Perry shares secret detail of her Coronation concert gown

King Charles & Queen Camilla Make Surprise Appearance on 'American Idol' After Coronation with Katy Perry & Lionel Richie

King Charles III and Queen Camilla appear on American Idol with judges Katy Perry and Lionel Richie

Katy Perry asks Stella McCartney 'hard hitting questions' about Britain at Coronation Concert