Har Mar Superstar was born on February 6, 1978 in Marshall, Minnesota, USA as Sean Tillmann. He is an actor and composer, known for Starsky & Hutch (2004), Pitch Perfect (2012) and Live Nude Girls (2014).

Was picked up by Warner Bros. as a recording artist, and was asked to open for both Incubus and the Strokes. In another incarnation was known as cult indie-rocker Sean Na Na in his native St. Paul, Minnesota and was also part of the band Calvin Krime in the late 90s. Has written songs for both Jennifer Lopez and Kelly Osbourne. Chose the name "Har Mar Superstar" from the local shopping center, Har Mar Mall. Raised Sean Tillman (of St. Paul bands Sean Na Na and Calvin Krime), Har Mar Superstar was originally his own alter-ego, a fictional "brother," Harold Martin Tillman. Only later did Sean take on Har Mar Superstar as his own stage name.