Rascal, 23, said that the incident took place after the Prince and his three friends made their entrance while performing boxing moves, and giving 'street handshakes' on their way to meet the performer.
“I never saw that one coming," the Telegraph quoted Rascal as saying. “Then Prince Harry came in and was joking around and being a bit cheeky, so I told him, 'If you weren't royalty I would've punched you in the face by now,' and he seemed to like that," he added.
According to the singer, Prince Harry fit in well backstage because he is a 'naughty boy', and he thinks the Prince and his friends are probably a bit wilder than his own crowd. Rascal will release his new single Holiday on August 31.