Last week, Leonardo DiCaprio joined activists and took to the streets of New York City to implore world leaders to take action against global climate change. But Leo isn't the only famous face to stand-up for what he believes in, and we've compiled a list of other celebs who have fought for something close to their heart...
George Clooney, 53
Against: Human Rights Violations
Why: Gorgeous George protested outside the Sudanese Embassy in 2012 to raise awareness about the alleged bombing of civilians and violence dealt out by the Sudanese government against their own citizens. After delivering a passionate speech, Clooney was arrested, led away in plastic handcuffs and fined $100 (Dhs367). But the protest did grab the attention of President Obama, who later met with George to discuss the issue. Job well done, Mr Clooney!
Kanye West, 37
Against: Wall Street greed
Why: In 2011 Kanye West stood out amongst the other protestors who rallied together for Occupy Wall Street, thanks to his gold grill and matching heavy-duty chain. The rapper, who is worth an estimated $155 million (Dhs570m), marched with the crowds to fight against Wall Street bailouts and a general sense of financial greed. Unfortunately, Yeezy had to leave almost straight away because "people were climbing on him" trying to meet the superstar rapper.
Rosario Dawson, 35
Against: President George W Bush
Why: Rosario joined a protest with around 400,000 others against President W Bush and the Republican National Convention at Madison Square Garden in 2004, but was arrested almost instantly. Wearing a black bandana to hide the bottom half of her face, Dawson was picked up by cops who said that protestors were not allowed to mask their identities and she had broken the law. It was a double hit for Rosario as the convention was delayed by a few hours, but still went ahead as planned.
Beyoncé, 33, & Jay Z, 44
Against: The acquittal of George Zimmerman
Why: The king and queen of the music charts were seen outside the New York Police Department headquarters in downtown Manhattan to demonstrate over the acquittal of George Zimmerman on charges of murdering black teenager Trayvon Martin. The couple were thanked by the hundreds of people who showed up and each held moments of silence for the late teen at their concerts last year.
Sean Penn, 54
Against: Military Rule in Egypt
Why: There’s not much that Sean Penn doesn't care enough about to stand up for, but one of his more surprising appearances was in Tahrir Square in Cairo, Egypt. Penn, joined by Egyptian actor Khaled El Nabawi, wanted the country's military rulers to speed up the transfer of power to civilians and end the emergency laws once used by the ousted president Hosni Mubarak against his opponents. Sean told Al-Ahram newspaper: "The world is inspired by the call for freedom by the courageous revolution of Egypt for its freedom."
Jessica Alba, 33
Against: The Hunting Of Sharks
Why: Jessica found herself in hot water after she plastered huge shark posters around town and took pictures of herself proudly doing it. However, a few days later she regretted her protest and said in a statement: "I got involved in something I should have had no part of. I realise that I should have used better judgment and I regret not thinking things through before I made a spontaneous and ill-advised decision to let myself get involved with the people behind this campaign."
Hayden Panettiere, 25
Against: Killing of Dolphins
Why: Hayden proved to be one of life’s real Heroes when she travelled to Japan to block Japanese dolphin hunters who were hoping to cash-in on the highly prized meat. After fleeing the country, a warrant for her arrest was put out and Hayden vowed never to do anything like that again. But then the warrant was dropped and the pint-sized blonde went back in 2010 to once again fight for flippers. Some people never learn.
Pamela Anderson, 47
Against: Cruelty to Animals
Why: So Pamela put her Peta crusade hat on to stop seals getting killed for their fur. She even presented a cheque for $1 million to Canadian sealers so they would retire and stop the seal hunt, but her plan kind of backfired. The owner of a shop in the region said business had gone through the roof since her visit and he'd sold more seal items than ever. Speaking to cbc.ca, shop owner Bernie Halloran said: "I've said this before, and I'll say it again, when celebrities come in, especially with the seal issue, it just angers people from the province."