One Direction did the Harlem Shake at their concert in London! The boys were answering Twitter questions when someone asked them if they could do the Harlem Shake, and they asked the whole crowd to join in! Niall Horan said, "Everyone stand still, then we'll just go mad." 1D just shot their first concert for their 3D movie, This Is Us in London, so we hope their crazy dance moves make it into the film! Check out the vid below!