Celebrity rivalries are as much a part of Hollywood as red carpets and the Oscars.

The late night feud between David Letterman and Jay Leno lasted for years. There were Katherine Heigl’s diva antics with her “Grey’s Anatomy” coworkers. Then, of course, there was an epic chicken grease fight between Sylvester Stallone and Richard Gere that came to blows. 

Whether it’s backstabbing, man-stealing, or social-media hating, some of the squabbles between these stars have been explosive and very public.

Here’s a look at the 20 most heated celebrity feuds of all time.

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Paris Hilton vs. Nicole Richie

Childhood best friends Paris Hilton and Nicole Richie dominated reality TV when they both starred together on Fox’s “The Simple Life” in 2003. But at the height of their fame, the two were suddenly at war.

“It’s no big secret that Nicole and I are no longer friends,” Hilton said in a statement to press in April 2005. “Nicole knows what she did and that’s all I’m ever going to say about it.”

According to People Magazine, Richie was jealous of the attention Hilton was getting from the media, angry that she wasn’t invited to some of Hilton’s events, and that she wasn’t included in Hilton’s appearance on NBC’s “Saturday Night Live” in February 2005. So Richie reportedly had a party to celebrate Hilton’s appearance on the sketch show, followed by a screening of Hilton’s notorious 2003 sex tape.  

“Paris was very hurt,” said People’s source. “She loves Nicole, but believes she is owed an apology.” 

Since then, the two have made up and even filmed two more seasons of “The Simple Life.” Richie told Andy Cohen on Bravo’s “Watch What Happens Live” in 2014 that even though she and Hilton don’t talk everyday, she considers her one of her very good friends. 

“The short answer is I haven’t spoken to her in awhile,” Richie said. “But we are very good friends and I love her and love her family and have a lot of respect for her.”

Sylvester Stallone vs. Richard Gere

Sylvester Stallone and Richard Gere were set to star together in the 1974 film “The Lords of Flatbush” until the two didn’t get along on-set. Gere’s role would later be re-cast. 

“We never hit it off,” Sylvester said in 2006. “He would strut around in his oversized motorcycle jacket like he was the baddest knight at the round table.”

The drama would get increasingly messy – literally. The two actors apparently also got into a physical fight over spilled chicken grease. 

“I was eating a hot dog and [Richard] climbs in with a half a chicken covered in mustard with grease nearly dripping out of the aluminum wrapper,” Sylvester said in the same interview. “I said, ‘That thing is going to drip all over the place.’ He said, ‘Don’t worry about it.’ I said, ‘If it gets on my pants. you’re gonna know about it.’ He proceeds to bite into the chicken and a small, greasy river of mustard lands on my thigh. I elbowed him in the side of the head and basically pushed him out of the car.”

Martha Stewart vs. Gwyneth Paltrow

These lifestyle gurus have been going at it ever since 2014. It all started when Martha Stewart slammed Gwyneth Paltrow for starting her own lifestyle business, Goop.

“She’s a movie star. If she were confident in her acting, she wouldn’t be trying to be Martha Stewart,” she told Porter magazine.

The drama didn’t seem to slow down when Stewart posted a pie recipe called “conscious coupling,” which was featured in Martha Stewart’s Living Magazine shortly after Paltrow filed for divorce from Chris Martin, calling the break a “conscious uncoupling.” A month later, Paltrow posted a similar recipe for “jailbird cake,”  presumably mocking Stewart’s time spent in prison back in 2004 for fraud charges. 

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