We all know that some of Justin Bieber fans are quite famous themselves. It turns out that Katy Perry is one of them. Recently the beautiful singer was spotted wearing a Justin Bieber t-shirt. The t-shirt that Katy Perry was wearing is a print of Justin Bieber’s Rolling Stone cover, and she combined it with a blue baseball cap and oversized sunglasses. You can see the pictures of Katy Perry when she was wearing Justin Bieber t-shirt for yourself Maybe someday Justin Bieber will return the favor and wear a Katy Perry t-shirt.