Meanwhile, Millie previously revealed her anxiety is worsened by fame.
She said: "I keep most things private in my life. Personally, I struggle with anxiety and in some ways, this has hindered it. When I'm having a bad day or I'm feeling very anxious, some things like when people say, 'Oh, you looked bad at this award show because you looked like this or you looked like that,' those things make me a little bit more anxious and that hinders me a little bit more."
Millie has a lot of "faith" in herself and has always spoken out.
She shared: "I do have a lot of faith in myself. As a young person and as a young girl I was very listened to so I'm very lucky that I get to tell my story of that experience. But listen, I came out of the womb having a voice. My mom was like, 'Mill, you need to shut up.' I've always had something to say!"