Taylor Swift doesn't want people to know she has a belly button.

The 'Blank Space' hitmaker admitted she chooses not to wear tops which reveal her midriff because she wants to keep her fans guessing as to whether she has a navel.

She quipped: ''I don't want people to know if I have one or not,''

Explaining why she chooses not to expose her abdomen, the 24-year-old star said she doesn't want to ''commit'' to ''the midriff thing.''

She said: ''I don't like showing my belly button,

''When you start showing your belly button then you're really committing to the midriff thing. I only partially commit to the midriff thing--you're only seeing lower rib cage.''

The 'Shake It Off' singer - who released her fifth studio album '1989' in October- continued to joke about her mystery midriff hinting she may in fact have a secret piercing which her fans are unaware of.

She said: ''I want that to be a mystery. As far as anyone knows based on my public appearances, they haven't seen evidence of a belly button. It could be pierced. They have no idea.''

The star also revealed if she was to get a tattoo which she didn't want anyone to know about, her tummy would be her body part of choice for the inking.

She told the December/January issue of Lucky magazine: ''If I'm going to get some sort of massive tattoo, it's going to be right next to my belly button because no one's ever going to see that.''