Listen to My Songs Know What You Did in the Dark (Light Em Up) (Workout Mix) online. My Songs Know What You Did in the Dark (Light Em Up) (Workout Mix) is an English language song and is sung by Power Music Workout. My Songs Know What You Did in the Dark (Light Em Up) (Workout Mix), from the album Pop Rocks - 25 Running Tracks (Unmixed Workout Music Ideal for Gym, Jogging, Running, Cycling, Cardio and Fitness), was released in the year 2014. The duration of the song is 3:37. Download English songs online from JioSaavn.