Leonardo DiCaprio delivers his remarks during the Paris Agreement on climate change held at the United Nations Headquarters on Apr. 22, 2016.
Leonardo DiCaprio's admission after his conversation with Sunita question his own role as the United Nations' "Messenger of Peace" for climate change. [Representative Image]Reuters

Celebrities put their superstardom for various uses, sometimes they only end up helping their own businesses. However, more often than not Hollywood A-listers also throw light on subjects that matter worldwide, much like Leonardo DiCaprio's Oscar acceptance speech this year.

Leo is not alone in his love for the environment, though. On World Environment Day 2016, let's take a look at some of the most green or eco-friendly celebrities of Hollywood:

  • Leonardo DiCaprio: Leo not only has a state-of-the-art green condo in New York City, he is often spotted riding a bike around downtown when he is not working. He also used his Oscar acceptance as a platform to speak about the environment and climate change that we can no longer ignore. "Let us not take this planet for granted. I do not take tonight for granted," Leo said.
  •  Natalie Portman: This Oscar-winning actress has been a vegetarian since childhood, long before being vegan was considered cool. She is also a supporter of animal rights, and even travelled to Rwanda in 2008 to help protect the silverback gorilla who are hunted for their fur. She has also introduced a line of luxury vegan footwear for Te Casan that is made entirely out of manmade materials.
  • Mark Ruffalo: This socially conscious thespian is an outspoken activist against the controversial oil and gas extracting process that could cause global warming and release carcinogens to the environment. In an article for Grist, Ruffalo writes: "Make no mistake. We are in a race against climate change. If we don't make dramatic changes — soon — it won't matter what political faction we align ourselves with or how much wealth we amass."
  • Ian Somerhalder: He may play a blood-thirsty vampire on the CW's "Vampire Diaries," but Somerhalder is a huge environmental and animal rights activist in real life. The Ian Somerhalder Foundation hopes to tackle the global problems and challenges that are "infinitely interconnected and co-dependent." To learn more about the initiative, you can visit the Ian Somerhalder website.
  • Cate Blanchett: This Academy Award-winning actress spent over $1.5 million to "greenovate" her family mansion. She even installed solar on the Australia's Sydney Theater Company. Blanchett also appeared on a TV commercial back in 2011 where she demanded that big polluters in Australia be taxed.