If you haven't seen it by now, the new interactive Old Spice Muscle Music video is viralling. Curious as to how it was done, The Atlantic spoke to Vimeo's Senior Manager of Strategic Sales Partnerships Abbey Morgan to find out how they had "put together such a seamless interface."

With over 1.5 million views, Wieden and Kennedy's latest video for Old Spice is a smashing success -- and it's only a day old. It's easy to see why; former NFL player and action movie star Terry Crews is literally playing cacophonous "music" with his bulging muscles, yelling entertaining non sequiturs like "GIMME A HAT!" and "SAUSAGES!" The spot fits the vibe of Wieden's game-changing 2010 campaign for Old Spice, which generated dozens of hilarious YouTube videos in real time, winning the Internet's heart for a day and making every other creative agency super jealous. Muscle Music taps the same Internet-friendly principles of absurdity, interactivity, and iteration -- at end of the performance, the video becomes interactive and viewers are invited to bang out their own ridiculous track on their QWERTY keyboards. The native Vimeo player lets users record and share their videos too, and the slick setup is fully embeddable.