Here are some details of stars and their involvement with the environment:

* LEONARDO DICAPRIO -- He started the Leonardo DiCaprio Foundation in 1998 to promote environmental issues. His film, "The 11th Hour", is an environmental documentary on the impact of humans on the planet. It includes former Soviet leader Mikhail Gorbachev and leading scientist Stephen Hawking.

-- However DiCaprio's earlier movie, "The Beach" was controversial in Thailand because of allegations by environmentalists that production work damaged a Thai beach paradise.

-- DiCaprio fiercely defended the project. "I don't want a bad reputation as somebody who endorses something hostile to the environment," said the Hollywood star whose role in "Titanic" made him one of the world's most bankable actors.

* AL GORE -- Al Gore, who narrowly missed becoming president of the United States, produced a documentary about a slideshow he has given on global warming, "An Inconvenient Truth". The short film was presented in Cannes in 2006 and won an Oscar this year.

* ROBERT REDFORD -- Thirty years on board of Natural Resources Defense Council, founder of Sundance Preserve, winner of 1993 Earth Day award, 1987 United Nations Global 500 award. In April 2007, he launched a weekly three-hour slot called "The Green", dedicated entirely to the environment, on his Sundance TV channel.

* CATE BLANCHETT -- She has plans to equip the Sydney Theatre Company building with solar panels and rainwater collection systems to make it completely eco-friendly. Her Sydney home is fully powered by solar energy.

* SPINAL TAP/LIVE EARTH -- The spoof heavy-metal band immortalised by the mock documentary "This is Spinal Tap" has reunited to join a campaign to save the world from global warming.

-- Director Rob Reiner, whose 1984 film set the bar for the "mockumentary" genre, has made a new short film called "Spinal Tap" as part of a campaign dubbed SOS/Live Earth. The band will also play in London at one of 7 Live Earth concerts on July 7.

-- Live Earth, on stages in all seven continents, will feature such artists as the Police, Madonna, and the Red Hot Chili Peppers.