Robbie Amell has played Fred Jones in two (2) of the live action Scooby Doo movies. The first was Scooby Doo The Mystery Begins and the second was Scooby Doo Curse of the Lake Monster. While the writers have started to take the characters down a path that I personally don't enjoy, Amell does well. However, Amell has never gone blonde for the role.
Other than the Scooby movies, Amell's movie roles to date include Cheaper by the Dozen 2.