Film/pop star and cancer survivor OLIVIA NEWTON-JOHN is undergoing the journey of a lifetime in order to raise funds for a cancer research hospital in her name. She's trekking along the Great Wall of China for 21 days with personal and celebrity friends, and ET is with her every step of the way!

"I'm just the face of the change and I'm able to help," says Olivia. "I think we're going to find a cure for cancer and hopefully this is going to be a thing of the past one day, and it will all be about wellness. Every step that we take is one step closer to that."

LEEZA GIBBONS is among the celebs joining Olivia on the extreme challenge that started April 7. Funds raised will go to the Olivia Newton-John Cancer and Wellness Centre in Australia.

"I'm here to honor Olivia and women all over the globe for whom cancer will become a reality," says Leeza. "What we want to to do is be one heartbeat to say we're going to change the way cancer and wellness is viewed around the world, thanks to Olivia."

For more information on the walk and the hospital, visit www.greatwalktobeijing.com and www.oliviaappeal.com.