When Jamie Lee Curtis found out that Lindsay Lohan, who was going to be playing her daughter, had starred in the remake of The Parent Trap (1998) she asked "Which twin did she play?", unaware that Lohan had performed both roles.
Kelly Osbourne originally auditioned as Anna (not as Anna's best friend) and was offered the part but decided to back out. Later she said people told her it was the biggest mistake she'd ever made due to the success of the movie.
Producer Andrew Gunn said he initially hoped Jodie Foster (who played the daughter in the original film, Freaky Friday (1976)) would be game to play the mother in the remake. Foster declined, in part because of concerns that the casting stunt would overshadow the movie's overall merit.