Mary Kate Schellhardt (born November 1, 1978) is an American actress. She is known for her role as Ellen in What's Eating Gilbert Grape, Nadine in Free Willy 2: The Adventure Home, and Jim and Marilyn Lovell's eldest daughter Barbara in Apollo 13. Other films in which she has appeared include Mr. Blue Sky, The Great Mom Swap, and 9-9-09. She has also appeared in the television series Windfall, Scrubs, House M.D., Private Practice, and Ben and Kate.