Is Demi Lovato a real christian?

So in a live chat from yesterday, she told that she had friends with benefits.. She has a cross on her hand, a tattoo on her feet with: Let go and Let god, she talks about God and I can go on for hours. But I just don't get it. Why would she do that? I am a real lovatic, but I don't know if I can be a big fan of someone of someone who does that..