Royal juice: Kate Middleton's diet secret.

THE Duchess of Cambridge helps keep her svelte figure in shape by making healthy juices with her Nutribullet blender.

Health conscious Kate Middleton is a fan of juice diets, it has been revealed. 

The Duchess of Cambridge began drinking natural fruit and vegetable juices before the royal wedding in 2011 to help her slim down for her big day.

She managed to dramatically drop over half a stone in four weeks, taking her dress size down to a small 6. 

Kate is reportedly still a fan of juice diets but doesn't follow such a rigorous regime and now only drinks juices for two days a month. 

The 32-year-old makes her juices with a posh kitchen gadget called the Nutribullet extractor.

The Nutribullet allows you to make either smoothies, shakes or soups. 

Kate's favourite is said to be a puree of orange, pineapple and banana. 

Nutribullet is becoming a must-have kitchen gadget - selling 3,000 units in one hour - and has already been snapped up by Hollyoaks actress Gemma Merna and Anthea Turner. 

The makers say it's "easy to clean" and looks slick on your kitchen worktop.