How to deal with a copycat friend?

Don't get me wrong I love my best friend but lately she's been copying me and even my other friends are noticing. It used to be really bad, but she settled down and now she's back. She copies my music taste the most. For example, I started listening to Ariana Grande's covers on YouTube and becoming a fan of hers. My friend looked and she said oh you like her? And I said yes so my friend looked her up and said she was a fan. She looked on my iPod and said I've heard this song before I think, and then went home and bought the songs. I was there and she went on her iPad and said "what's that song you said you liked?" then bought it. She told me she hated Miranda cosgrove and I said I liked her, and now she's a fan of hers. I swear it's everything I listen to! And she also tries to take my style and all. I confronted her today and she just gave me a crazy look. What can I do?!