EASTER EGG: There are several faces hidden in the image throughout the movie. In order of appearance: 1. During the opening pan across the countryside, when you see the unicorn, the side of the wall where the branches are broken forms the silhouette of a face in profile. The broken part of the wall makes the forehead, nose, and mouth; the branches make the hair, eyebrow, and eye. 2&3. There are two hidden faces in the pages of the magic book when Mandy (Minnie Driver) first opens it. 4. When Prince Char and Ella see the giants working in the field, there's a face hidden in the hill on the left side. You can see it in the shot that starts on the guard towers and pans right to the field (the last shot of the giants). It might also be visible in the very first shot of the giants, but only in the wide-screen version. 5. When Ella is chained to the tree, there is a small face hidden in the middle of the tree in between the two outreached branches (that look like short arms). It can be very hard, if not impossible, to see on some copies of the film (especially if the print is kind of dark).
The first song Ella sings, "Somebody to Love" was not the original song choice. Tommy O'Haver had discovered that Anne Hathaway didn't have very good chemistry with their first choice, a more classical "fairy-tale" song. O'Haver and Hathaway were relaxing when she starting singing along and dancing to the song that was currently playing: Queen's "Somebody to Love". They both decided that "this was it".
The trivia item below may give away important plot points.
There are several references to Cinderella - Ella gets a step-mother and two nasty step-sisters; one of her stepsisters tells Ella to go home and clean the fireplace; Ella is made to steal glass shoes/slippers; Ella has a fairy godmother who puts her in a gown for the ball; the stroke of midnight is significant; as another word for "Char" is "Cinder", when you combine the names it becomes "Cinder-Ella". This is actually because the original book by Gail Carson Levine was supposed to be a spin on the Cinderella story. In the book, many of these connections are made much clearer. Also, Char's full name, Charmont, is actually supposed to be a play on the name Prince Charming.