Marking his return to London with a solo-exhibition at Lazarides, JR brought along the "Inside Out" photo booth truck and gave people a chance to have their portraits plastered outside of the Somerset House. When the project passed through the boroughs of New York, an estimated 13,000 people contributed their portraits, including JR's friend and collaborator, Pharrell Williams. For more photos of the London premiere, head over to ArrestedMotion and if you're in the area you can see the photos in person and participate between the hours of 1p.m. and 7p.m. from now until October 11.