Alex Jones welcomes you to week four of Tumble, with a place in the semi-finals up for grabs. The daring celebrities and their professional partners throw themselves into trampolining 10 feet in the air and rhythmic gymnastics featuring ribbons, hoops, balls and a whole load of weird and wonderful props. The judging panel is led by Olympic legend Nadia Comaneci and Commonwealth gold winner Louis Smith. And roll up, roll up for Circulus, with a very modern circus performance with trapeze and bungee straps. It's gymnastics but not as we know it! It's time to Tumble.