Hypothetically if you already had the DVD and hypothetically accidentally happened to watch it then that is okay
BUT if you in a premeditated manner went out and purchased or rented the movie in physical (DVD/Blu-ray) or digital form or streamed it knowing that the answer to a quiz question may be contained within, then that would be against the rules and spirit of the quiz and I would have to whip out my quiz master's red pen and strike out the answer and issue a formal warning and deduct 5 points.
The above is just hypothetical as I know no Princess would ever employ such devious tactics