Claire Danes for Natalie Portman in Romeo + Juliet (1996)
She's too little! That was essentially the reason Portman didn't end up in Baz Luhrmann's unconventional Shakespeare adaptation. The director flew her to Sydney, Australia, to film some sample scenes with male lead Leonardo DiCaprio, and the result was unsettling.
"Although she's a fantastic young actor, she's a tiny little girl and Leonardo's six feet tall," Luhrmann said. "He's 21, but can look 18. She made him look all of 21, and it just became obscene." Portman essentially agreed, saying: "They said it looked like Leonardo was molesting me when we kissed. It was really disappointing, but I wouldn't have wanted to be in the movie and have it look wrong."
Sarah Michelle Gellar, Kate Winslet, Christina Ricci and Jennifer Love Hewitt were also considered before the decision was made to go with Danes.