Kate HudsonActress Kate Hudson does not know the sex of her unborn child but she is predicting that it will be a girl based on 'The Pendulum Test.'

Hudson was on ET Online promoting her upcoming movie 'Something Borrowed' when the interviewer asked her if she knew what the sex of her unborn baby with Muse frontman Matt Bellamy was.

The 31-year-old actress said she did not know the sex of the baby but she believed the unborn child was a girl based on the pendulum test.

Hudson went on to explain and demonstrate the pendulum test which she jokingly called 'witchy.' "So here's the pendulum test. You take a piece of your hair, and you take a ring... and you string it through. And then what you do is you hold it over your stomach."

She continued, "And [if it moves in] a circle, it's a girl, and a boy [the pendulum] goes back and forth."