Nicki Minaj vs Mariah Carey: Despite denials from both parties previously, a new video shows Nicki Minaj launch into an x-rated rant at fellow American Idol judge, yelling, "I told them, I'm not f**kin' putting up with her f**kin' highness over there." The live shows should be worth watching...

Madonna vs Lady Gaga: Lady Gaga has always cited Madonna as one of her biggest influences - so it must have come as quite a blow when Madonna began promoting her MDNA tour by criticising her young pop rival. Madonna called Gaga 'reductive' when asked about similarities between her track 'Express Yourself' and Gaga's 'Born This Way'. Madge then included a cover of Gaga's hit in her live shows, prompting Gaga to speak out about the cover at a live show in New Zealand. "It sometimes makes people feel better about themselves to put other people down or make fun of them or maybe make mockery of their work. And that doesn't make me feel good at all," said Gaga. Later, she declined Madonna's invite to join her on stage for a duet.

Lil Kim vs Nicki Minaj: When this rivalry started it was Nicki who looked like she was using the public war of words to make a name for herself as a rising rapper on the cut-throat hip hop scene. However, as her star rose to the point she is now one of the biggest pop stars in the world, Lil'' Kim found herself further and further in the wilderness and continued the rivalry as a way of keeping herself in the limelight. Needless to say, Minaj has less time for insulting Kim these days.

Tulisa vs Kelly Rowland: Kelly Rowland's stint on UK X Factor didn't go quite to plan and she certainly didn't make many friends on the show, with a rift between her and Tulisa harldy helped when the N-Dubz star accused one of Rowland's acts of bullying Little Mix backstage. Tulisa has since claimed that Rowland ignored her while she was partying in an LA nightclub and when asked by Sara Cox recently if she missed the Destiny's Child singer, she said: "Um. No comment."

Amy Winehouse vs Katie Melua: This was a slightly one-sided rivalry, with Winehouse taking a dislike to the amiable Melua from the off. Amy accused the folk singer of getting her boyfriend to write her songs for her and later said she would ''rather have cat AIDS'' than listen to one of Katie Melua''s songs during a appearance on Never Mind The Buzzcocks.

Cheryl Cole vs Charlotte Church: Despite recently telling Gigwise that she had never met Cheryl Cole, Charlotte Church and the 'Call My Name' chart topper were once involved in a nasty war of words. Church is said to have called Girls Aloud 'five dogs without balls', prompting Cheryl Cole to reportedly respond saying, "I don't know who she and her scabby boyfriend think they are. He's a posing idiot who looks like a girl. And she’s not even gorgeous. She's a nasty little piece of work with a fat head."

Rihanna vs Joan Rivers: When it comes to international pop stars, it''s hard to best Rihanna, but when it comes to acid-tongued divas, comedian Joan Rivers is at the top of her game. An unlikely war of words broke out between the two in August 2012. After Rihanna admitted she was still in love with her violent ex-boyfriend, Rivers tweeted: "Rihanna confessed to Oprah Winfrey that she still loves Chris Brown. Idiot! Now it''s MY turn to slap her," prompting Rihanna to respond by poking fun at the comedian''s age. "@Joan_Rivers wow u really do get slow when you''re old huh?" said the singer - before deleting the tweet.

Courtney Love vs Kelly Osbourne: It's trickier to find someone who Courtney Love hasn't been at war with, but her feud with Kelly Osbourne was one of her more bizarre. In a video message, Love claimed to have saved Osbourne's life on several occasions, tweeting: "I've saved her life twice. I've done CPR, I've put things in her boobs. Oxycontin, cocaine, foaming at the mouth." The incident is said to have been sparked when Osbourne referred to Courtney Love as a 'crackhead' on US TV show, fashion police.

Britney vs Christina: It was inevitable that the two biggest female popstars of the late 90''s would be rivals but this particular rivalry got personal when Christina was reported to have hooked up with Britney''s ex Justin Timberlake when the pair toured together in 2001. Britney is also reported to have written a song for one of Aguilera''s albums, when Christina found out she deleted it immediately. However, the pair are closer these days now that their musical careers are less than stratospheric and they spend their time judging on X Factor USA and The Voice respectively.

Lily Allen vs Katy Perry: An ill-advised comment from US star Katy Perry sparked a war of words with Lily Allen in 2009 when Perry described herself as a "fatter version of Amy Winehouse and the skinnier version of Lily Allen." Never one to hide her feelings, Allen responded, saying: "It's, like, you're not English and you don't write your own songs — shut up!" and threatening to reveal secrets on the US star on Facebook. If only someone could make celebrities' private Facebook messages public as well as everyone else's...

Sugababes: The original line up of the Sugababes (Mutya, Keisha and Siobhan) were notoriously bitchy and would constantly row behind the scenes. The majority of the tension reportedly came from Mutya and Keisha''s close relationship which often left to Siobhan feeling isolated. The two girls also created a special language they would use to bitch about Siobhan, which can''t have helped relations much either. The three girls are back together now, with all fingers crossed they have put the past behind them and can move forward minus the fights.

Lady Gaga vs Kelly Osbourne AND Sharon Osbourne: It takes a brave woman to take on an Osbourne, but hats off to Gaga, who felt the force of both in early 2013. Kelly openly criticised Gaga's 'Little Monsters' for calling her fat and suggesting she kill herself. Gaga responded, saying that Kelly shouldn't criticise others' appearance on her Fashion Police show. Mum Sharon waded in, calling Gaga 'abhorrent' and a 'bully'. No one involved here is known for backing down - expect this one to run and run...