Helena Bonham Carter was pregnant throughout filming with her and director Tim Burton's second child, and she insists (accurately) that the size of her breasts noticeably changes throughout the film, as filming was done out of sequence.
Helena Bonham Carter underwent extensive vocal lessons and studied baking in preparation for her role.
Anne Hathaway was almost cast as Johanna but Tim Burton wanted a complete unknown for the role and settled with Jayne Wisener. Meryl Streep, Imelda Staunton, Cyndi Lauper and Emma Thompson were all considered for the role of Mrs. Lovett.