She hired two make-up artists to prevent HER looking like one of the ogres in the movie.
A red rash broke out on her face before the animated movie was screened at the French film festival.
The beauty experts spent two hours trying to make Cameron, 31, look her best though her reddened cheeks suggest they had to lay on the rouge quite thickly.
A source said: The zits flared up the night before it was a case of all hands on deck to make her look her normal self. They worked for ages to give her a perfect complexion. Cameron has problem skin like a lot of girls. It tends to flare up when she is stressed or has too many late nights.
But she looked great for the big night, though she headed home from the party afterwards before midnight for a good nights rest.
Click the link to see the before and after pictures.
I know we read a while back that she requires a trowel to apply her makeup (when she isn't insisting that her assistant shave her armpits for her, that is).