Dakota Fanning reportedly did not want to shave her head

Dakota Fanning and her sister Elle Fanning aren't irreplaceable after all.

"Little Miss Sunshine" star Abigail Breslin will step into the younger Fanning's role, while Sofia Vassilieva is in talks to replace Dakota Fanning in "My Sister's Keeper," reports Variety.

The Nick Cassavetes-directed drama centers on a young girl (Breslin) who sues for emancipation from her parents (one played by Cameron Diaz) after she learns that she was born as a genetic match to prolong the life of her ill older sister (Vassilieva). Alec Baldwin will play the child's attorney. Joan Cusack will also star.

Rumor has it that Dakota Fanning refused to shave her head for the role and thus dropped out, taking her sister with her. Production will begin in March.

Breslin, 11, receieved an Oscar nomination for her supporting role in "Little Miss Sunshine." Her credits include "Raising Helen," "The Santa Clause 3," "No Reservations," "Definitely, Maybe" (in theaters beginning Feb. 14) and the upcoming "Nim's Island" and "Kit Kittredge: An American Girl."

Vassilieva, 15, starred as Cindy Brady in the TV movie "The Brady Bunch at the White House," as Eloise in the TV movies "Eloise at the Plaza" and "Eloise at Christmastime" and as Ariel Dubois on "Medium."