Derek Hough Rips His Shirt Off for 'American Ninja Warrior,' Completes Course - Watch now!

Derek Hough flexes his biceps after reaching the top of the American Ninja Warrior course during the Red Nose Day special! The 32-year-old World of Dance star helped raise a lot of money for charity by completing the course like a true pro. After Derek fell off an obstacle into a pool of water, he