Dianna may be busy filming Glee at the minute, but she's about to become a big screen sensation too, with her sci-fi thriller, I Am Number Four released today
The sci-fi adventure also stars Alex Pettyfer, who passes as a typical high school student to escape a deadly enemy seeking to destroy him. Three like him have already been killed and he is Number Four.
Watch our exclusive clip where Alex meets number six
By Hayley Spencer