World Vegan Day is observed on 1 November, 2015, with veganism being celebrated the entire month. Vegan Day was first observed on 1 November, 1994, as a way of commemorating the 50th anniversary of the UK Vegan Society. Along with celebrating the start of the Vegan Society, Vegan Day is also an opportunity to promote the benefits of a vegan diet and veganism in general.

A vegan, as we know, is a strict vegetarian who does not even eat or wear any animal products, including milk, honey, leather or wool.

On this day, we list out some of the hottest Hollywood celebrities who will inspire you to give up animal products for a better and healthier lifestyle.

Brad Pitt: The actor is an ardent animal rights activist, who had also once confessed that he hates it when wife Angelina Joile and their children eat animal-based dishes. Brad is actually considered to be the biggest symbol of how to adopt a completely vegan lifestyle, and apparently, he's been a vegan for years.

Ellen DeGeneres: The 57-year-old host and her partner Portia gave up meat and dairy products in 2008 and became full-fledged vegans.Once a steak and sausage lover, Ellen expressed why she chose to become a vegan on the PETA blog page. "I personally chose to go vegan because I educated myself on factory farming and cruelty to animals, and I suddenly realised that what was on my plate were living things, with feelings. And I just couldn't disconnect myself from it any longer. I read books like Diet for a New America and saw documentaries like "Earthlings" and "Meet Your Meat", and it became an easy choice for me," she wrote.

Ariana Grande: In 2013, the singer took to Twitter to announce her switch to a vegan diet. Voted as PETA's sexiest vegetarian in 2014, she tweeted: "I love animals more than I love most people, not kidding. But I am a firm believer in eating a full plant-based whole-food diet that can expand your life length and make you an all-round happier person."

Natalie Portman: The actress has been a vegetarian for a very long time, but switched to a vegan diet in 2009 after reading Jonathan Safran Foer's "Eating Animals". But she reverted to vegetarianism during her 2011 pregnancy and post-delivery, she went back to being a vegan later. In fact, it has been reported that her 2012 wedding featured an all-vegan menu.

Alicia Silverstone: She is one of the most well-known and outspoken vegans in Hollywood. The 38-year-old actress and activist has been a vegan for nearly two decades. In fact, she has even written a vegan cookbook, "The Kind Diet," and launched a blog, "The Kind Life", that focuses on vegan and vegetarian food, environmentally-sensitive fashion items, and environmental issues.

Carl Lewis: World-famous track runner and Olympic gold medalist Carl Lewis had once said that he went vegan after meeting two people, a doctor and a nutritionist, who inspired him to switch veganism. He also mentioned that he had the best race of his life at the 1991 World Championships, after he turned vegan to prepare for the race.

Mike Tyson: This heavyweight boxing champ turned vegan in 2010 and is said to have lost 100 pounds.

Jared Leto: Awaiting his next release "Suicide Squad" where he plays the Joker, Leto attributes his youthful good looks to yoga and vegan diet. The actor who has been a vegan for over two decades, said: "I'm pretty healthy so I think that helps a lot. I'm a vegan. I respect the environment and I do my best to spread the importance of such an issue."

Ellie Goulding: The "Burn" singer has been a vegetarian for long before quitting consumption of all animal-based products. Ellie was once quoted as saying that she credits the diet for helping her feel leaner and stronger.

Pamela Anderson: The most famous of all, the "Baywatch" star gave up eating animal products when she started working with PETA. And the actress continues to promote a meat-free life till date. There are reports that suggest that by the end of the year she will debut two lines of vegan accessories.

Jessica Chastain: The actress in fact got her mother -- Jerri Hastey, a chef -- to switch to veganism as well. Jerri owns and operates a vegan food truck, Seed on the Go, in Santa Rosa, California. While expressing her thoughts on being a vegan, she said: "I don't normally get into this, but I'm a vegan."

CLICK HERE to view the list of other famous celebrities, musicians, athletes including Alanis Morissette, Alicia Silverstone, Anoushka Shankar, Ariana Grande, Betty White and others who turned vegan.