A radiant Cameron Diaz hit the red carpet for the premiere of her new movie My Sister's Keeper.

The movie, which is generating a lot of buzz, is the story of a young girl, played by Abigail Breslin, who was born to be a donor for her sister who's dying of cancer.

“I'm a designer baby made in a dish to provide spare parts for [my sister],” says Breslin’s character.

Diaz plays the girls’ mother. “There is no right or wrong. You do your best,” says Diaz.

My Sister's Keeper is based on a best-selling novel of the same name. However, the story is not just the stuff of Hollywood fantasy, it actually happened 20 years ago.

Anissa Ayala was 16-years-old when she was diagnosed with Leukemia. Without a bone marrow transplant, she faced certain death. Her story gripped the nation and made the cover of Time magazine.

Her parents searched high and low for a bone marrow donor, but they failed to find a match for Anissa. Desperate, they decided to have a baby in the hope that the child would be a match for her dying older sister.

The family, who live in Southern California, faced fierce criticism, and even received hate mail for their controversial decision. But baby Marissa was a perfect match and when she was 14-months-old, she donated bone marrow to her big sister and Anissa was cured.

Today Marissa’s grown into a stunning young woman. A shy, humble teenager, she is in awe of her big sister, now 37 and to this day, cancer free.

“Life is great. My health is good...I’ve got a sweet angel sitting next to me,” says Anissa, giving her little sister a squeeze.

Anissa, who is engaged to be married, works tirelessly to raise money for The Leukemia & Lymphoma Society.

“The odds were completely against me to pull through it,” she explains. “I promised I would give back.”

Janine Ingram, the Executive Director of The Leukemia & Lymphoma Society tells INSIDE EDITION, “It’s invaluable. It is her story, her willingness to tell her story as a Leukemia survivor, as somebody who has gone through this treatment is incredibly valuable.”

Marissa also tells INSIDE EDITION she's not done giving to her sister yet. Anissa's ovaries were damaged by the radiation used to treat her cancer, so Marissa is now offering to donate her eggs should Anissa decide to have a baby some day. “She'd be a great mom. I think you'd be a great mom,” she says, turning to face her big sister, before the two exchange a big hug.