The opera singer started following a pescatarian diet - which is essentially a vegetarian eating plan but allows the ingestion of seafood - five years ago and is thrilled to have relocated to Los Angeles to take part in reality TV show `Dancing with the Stars` because she loves the sushi in the city.
She told People magazine: "It`s not for animal rights - it`s something I tried and it seemed to suit me. I love sushi, and I know LA has the best, best sushi."
Although Katherine is a world renowned opera singer she admitted her musical tastes are quite eclectic and she especially loves rap and R&B.
Katherine, 31, explained: "Because I sing classical and opera, people assume that`s all I listen to. But I`m like any other girl of my age. I like to go out and dance with my friends and listen to pop music. I love everything from hip-hop and rap to jazz, blues, R&B, anything. I love Nicki Minaj, love Beyoncé, Rihanna and Lady Gaga."
Katherine split from her TV presenter fiance Gethin Jones in December and says she still isn`t ready to start dating again but is thrilled to have a new challenge to throw herself into with `Dancing with the Stars`.
Katherine - who has been partnered with professional dancer Mark Ballas on the show - said: "I`m not yet ready [to date. It`s all too soon. But I think it`s great to have a new physical challenge, something to throw myself into."