Jamie looks quite different from Mandy in real life. Mandy is a natural blonde. She was that way on both of her early albums ("So Real" and "I Wanna Be With You") as well as her screen debut in "The Princess Diaries" (where she played Lanna the bitch cheerleader) and dyed her brown for AWTR. She later dyed her hair a darker color for "How To Deal" and cut her hair for the film (for about 15 minutes she has long hair and then cut it as a plot point). Since then she's changed it a number of times going from blonde ("All I Want" "Bubble Boy") to black in several films. She seems to like the darker color, but as far as I know she's really a natural blonde.