16 Year-Old Ed Sheeran auditions for Britannia High (2007)

Britannia High was a short-lived UK TV series (a scripted musical drama, like Glee and Fame) about a performing arts school. (It wasn't a real school!) Ed Sheeran was one of the young hopefuls who endured a grueling audition process in 2007 for the six lead roles. The casting team recognized his unique talent and appeal, but he wasn't cast. (You can see how much his dancing has improved by watching his video for Thinking Out Loud.) These are excerpts from a 44 min behind the scenes documentary.
Another favorite of mine, Matthew James Thomas, played Jez in the 9 Britannia High episodes and went on to star in Pippin on Broadway.
For Pixie Lott's moments and two extra clips of Ed missing here, see this video:    • 16 Year Old Pixie Lott Auditions for ...  
Please, no disrespect in the comments to any of the young performers. Don't be cruel.