Yep, mum was right! The deepest muscle in your tummy, your transversus abdominis, directly affects your posture so sitting and standing up straight will strengthen your core. Have an office job? Try holding your tummy flat while sat at your desk to give your waist a sneaky little workout.

To get Salma Hayek's red carpet posture (and teeny waist), pull your shoulder blades back and your belly button towards your spine both when resting and exercising.