Here's a look at some of the recent celebrity feuds, and how they played out in the media.
1. Elton John vs. Madonna
When Madonna was nominated for the best live act award at Britain's Q Awards last October, John lashed out at the Material Girl.
"Madonna? Since when has lip-syncing been live? Anyone who lip-syncs in public on stage, when you pay 75 pounds to see them, should be shot. … But do I give a toss? No," he said.
The Rocket Man has gone ballistic on many stars in recent years, calling Keith Richards "a monkey with arthritis" and describing George Michael as being in a "strange place" in his life.
Madonna's publicist shot back that the star sang every note on her recent tour. John finally promised to apologize to Madonna, who didn't win the award for best live act. But at least she didn't lose out to Ashlee Simpson.
2. Hilary Duff vs. Lindsay Lohan
What a nasty love triangle. Lindsay Lohan had been dating Aaron Carter, and then, in 2003, he moved on to Hilary Duff. When Lohan showed for the "Cheaper by the Dozen" premiere, Duff and her mom were outraged and reportedly asked security guards to make Lohan leave, sparking a little confrontation.
Duff later accused Lohan of bad-mouthing her to Chad Michael Murray, her "Cinderella Story" co-star, in a yearlong media battle.
The song "Haters" on Duff's CD last year is said to be directed at her rival. The lyrics include: "You look so clean but you spread your dirt/As if you think that words don't hurt/You're the queen of superficiality/Keep your lies out of my reality."
3. Hilary Duff vs. Avril Lavigne
Duff's other recent row came after she criticized Avril Lavigne. Lavigne had been angry with fans for copying her style, according to one news report, and the former "Lizzie McGuire" star thought that was poor form.
Lavigne denied that the article was true and called Duff a "goody-goody" and "mommy's girl" in a Newsweek interview. The Canadian pop rebel then sent this message to Duff via a Boston radio station: "Don't talk trash with me."
Duff eventually backed down and apologized while promoting "A Cinderella Story."
"I'm genuinely sorry that I upset her because I totally respect her and totally love her music," Duff said.
4. Jay-Z vs. R. Kelly
The rapper and the R&B legend billed their tour last year as "The Best of Both Worlds," but a month after they hit the road, it ended at New York's Madison Square Garden in disaster.
Kelly had been complaining that Jay-Z's entourage had been working with lighting technicians to undermine his part of the show. Then, in the middle of his act, Kelly walked off stage, saying someone was waving a gun at him.
After the show, Kelly said he was jumped and doused with pepper spray before he could get back on stage, blaming Jay-Z for the incident.
Kelly was booted from the tour, and subsequently sued for $75 million. Jay-Z replaced him with other acts, but many dates were canceled before the whole thing was called off.
Ironically, the two musicians had recorded an album for the tour, titled "Unfinished Business."
5. Jon Stewart vs. Tucker Carlson
When Jon Stewart came on CNN's "Crossfire" last summer to promote his book "America," he took some swipes at cable talk shows. "Come on, be funny," said host Tucker Carlson. Stewart shot back, "I'm not going to be your monkey."