It's being called one of the most exciting chart battles in recent pop history.
New singles from US pop divas Katy Perry and Lady Gaga are set to battle for the No. 1 spot on this week's Billboard Hot 100 chart, currently occupied by Robin Thicke's Blurred Lines.
Perry's Roar and Gaga's Applause were both leaked on Aug 10 and instantly started a paws-versus-claws war among their fan bases, the KatyCats and Little Monsters.
It got serious enough for Gaga to step in at one point and beg for peace, tweeting: "Let's make 2013 a year where music/talent/artistry is more important than gossip/fanwars I respect all fanbases 4 their passion #BeTheChange".
But the fan wars were just the start of a flurry of Perry-versus-Gaga drama.Both critics and fans have weighed in, and overwhelmingly the winner seems to be Perry, whose single has been praised as being pure pop perfection while Applause has been derided for not living up to the hype.
Though Roar has been beset by plagiarism accusations, the song was projected to sell 525,000 downloads by the end of last week, according to Billboard.
In comparison, Billboard projected Applause - from Gaga's upcoming album Artpop - to sell less than half that number. No wonder then that Gaga's feeling the pressure.
After the leak of Applause, she took to Twitter to dangle this to the Little Monsters - buy her single and stand a chance to meet her in person.
What irked fans was a follow-up tweet that said in no uncertain terms that the more copies one bought, the better the chances.
"The 2 fans w the most purchase/gift screenshots, radio requests, 'Applause' selfies/video, will fly international to meet me+watch the show!" tweeted Gaga.
It was a move that was roundly criticised by both fans and the media, who said her method of trying to inflate sales was hardly fair to her diehard supporters.
Influential gossip blogger Perez Hilton joined the fray, tweeting his support for Roar and making videos and mash-ups to prove that not only was Applause the lesser single, but that it may have been a rip-off of Madonna's song Girl Gone Wild.
In a tweet, Gaga plead with her fans to ignore him. "Please monsters do not be affected by someone like this NOTHING merits this kind of hatred. Im ok & I always survive. Ignore him. Just Dance," she wrote last Friday.
In any case, the pop stars themselves have been playing nice in interviews.
"It's all about the music and I really agree with her message," Perry, 28, said of Gaga's track to US radio DJ Carson Daly. "I've always been a fan of hers and I like to see her evolution.
"I think that it's also nice that we're all in the same kind of cycle together because it really keeps us both on our toes... It's not that we feel competition, it's that we keep each other on each other's toes and it's a healthy thing."
Gaga, 27, returned the favour during a chat on US DJ Ryan Seacrest's radio show, saying: "Because look, we both just happened to want to put our singles out within a week of each other. And it's not necessarily convenient for everyone and may be a little bit awkward... But we don't need to force-feed this negativity into it until everyone explodes.
"I really like Katy Perry. And I like her fans."
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