Harry, like most of the Royals, is famously dim, and his his case was only any good at art at school - he was an artist.
He is a massive R&B fan though, and, as Royals do, got to meet his hero. Harry was going through a teenage rebellious phase at the time, so insisted on renouncing his official title.
So impressed was the RnB star with the young Harry that he adopted his introduction as his new stage name - "The artist formerly known as Prince".
Harry also changed his name by deedpole in tribute and is actually "Squiggle Windsor" on all official documents.