Of all of the "What the...?" moments in the trailer for the new Kevin Hart/Dwayne Johnson movie Central Intelligence, the moment where a teenaged, less fit version of The Rock's character sings En Vogue in a locker room is the most memorable. It was also, it turns out, pretty hard to make. The process required VFX teams to film Vine star Sione Kelepi (aka Sione Maraschino) and capture his movements, make 3-D facial scans of Kelepi and Johnson, and then combine them into one performance. Find out how they did it in the Design FX video above.