Prince William and Kate Middleton broke up briefly in 2007 during their dating phase.

A rediscovered tape from a Princess Diana tribute concert in 2007 showed William and Harry introducing acts.

Judi James' analysis revealed William's awkward dad-dancing and Harry's expressionless reaction.

While William tried to encourage Harry to join in, he appeared to be talking to Chelsy, his fiancée.

Kate was seated several rows back, possibly due to the break-up.

Chelsy noticed William's attention-seeking dance and immediately reported it to Harry.

Harry's reaction was that of a teenager embarrassed by his father's party antics.

William seemed to gloat to Kate about his independence and enjoyment without her, but he wasn't prepared for this type of body language ritual.

This was most likely a small swan song before William married Kate, leaving everyone wondering what other surprises the royal couple had in store.