Celebrities hail Nelson Mandela on eve of birthday

While Nelson Mandela remains in critical but stable condition in a hospital in Pretoria, South Africa, the world prepares to celebrate his 95th birthday.

A host of celebrities, including the Dalai Lama, former president Bill Clinton and Richard Branson, founder of the Virgin Group, have voiced their appreciation for Mandela.

Mandela Day is celebrated July 18, the birthday of the former South African president and political activist. It was created In an effort to promote global peace and inspire individuals to take action to help change the world for the better.

In a video clip on mandeladay.com, Mandela explains that his birthday will not be a holiday, but rather "a day devoted to service. It is our hope that people will dedicate their time and effort to improve the conditions within their own community."

"You're an example to us all of perseverance, strength, wisdom and grace," said Branson, who is one of many celebrities encouraging people to do their part in celebrating Mandela Day.