I understand you did a Madonna cover….
Yes, “Oh Father.” I personalized the words to make sense to me.

Have you met Madonna before?
Never. But I grew up wearing fingerless gloves because of her. Then one day about three years ago she put one of my songs, a remix of “Breathe Me,” on her iTunes playlist. She said it was a great song to work out to. Then I got excited, because someone who was staying at my house was working for this jeans company and Madonna had asked for a bunch of their jeans. This girl was packaging the jeans at my house, so I slipped a note in one of the boxes for Madonna and said, “Hi, this is Sia. You put my song on your iTunes playlist and I wanted to say thanks. I love you.” And that’s the extent of our relationship.

Did she find the note?
I doubt it. But if she tried on the jeans I’ve come pretty close to her bum! [Laughs]

Source: Spin Magazine, All About Madonna