Last month, Li was asked to speak at the UN Climate Change Summit convened by Secretary-General Ban Ki-moon at the UN headquarters in New York. She reaffirmed her commitment to environmental protection, calling for more youths to get involved in the movement.

Despite her rising profile in Hollywood and numerous film awards since 1994, Li says she was "a little nervous" ahead of her UN speech.

"It was such an honor to speak in front of those distinguished guests, including the heads of state," says Li.

"I realized I was shouldering a bigger responsibility when I stood on the podium to make the call for action and to make action really happen," says Li.