Katy Perry is excited about 7-year-old rapper Matty B doing a hip hop remix of her new single ‘Firework’. “So.. I met this amazing 7 year old kid, Matty B and he told me he was gonna do a ‘Firework’ remix and he did,” Perry writes. “It’s amazing! Shout out to MattyBRaps!!! I wanted to say you’re SO adorable! I wanna keep you! Good luck firework!” Watch it via YouTube below.