The 24-year-old actor said on US talk show Live With Regis And Kelly that he auditioned for a role in Glee three times before he finally got the part.
“I would have never admitted that I cut my hair for an audition, unless I got the part,” he said.
He then added: “I would never have got it if I had kept my hair.”
Pointing to a picture of himself with long, curly hair, he said: “This is what I really look like. I have big hair, that is who I really am.”
'This is a lie,” he then joked, pointing to his new shorter hairstyle.
The clean-cut star later played the piano and sang a cover of Paul McCartney’s Silly Love Songs.