Is she or is she not? Speculations over Rihanna and Chris Brown getting back together have been going on ever since the singers came back together for the music single Birthday Cake, two years after Rihanna walked out of an abusive relationship with Brown.

Although Rihanna recently said in an interview that she was single and did not like it, slashing rumors of getting back with Chris, it has not stopped the singer from picking up a verbal fight with Brown's current girlfriend on social networking site Twitter, according to Radar Online and The New York Post.

Though some messages are cryptic, some are pretty explicit comments, including one, in which Karreuche Tran, Brown's current girlfriend, compared the situation to that of Brad Pitt, Angelina Jolie and Jenifer Anniston's. I'm Angelina, you're Jen, she wrote. 

The singer and the Vietnamese model have been fighting publically and the contention assumedly started when Rihanna posted a photograph of a bag of rice cakes wearing sunglasses with gold earrings, and the caption, Ima a make u my b****, said a report in Daily Mail.

Possibly, the picture and the caption were posted as a taunt to Karreuche. Also, Rihanna responded to a follower who wrote: @rihanna save me some rice cakes rather hungry, saying, Kinda DRY tho.

It was in response to those posts that Karrueche reportedly posted on her Facebook page: I'm Angeline (sic), you're Jen. C'mon you see where Brad is at.

The model also added more comments, explicitly mentioning the 24-year-old singer's name: Let me clear the air, if you have fenty at the end of ya name or your default Is Rihanna you have a better chance of winning the lottery than ending up on my friends list.

However, Karrueche denied that she even had a Facebook page, reported The Daily Mail.

Taking matters from bad to worse, Rihanna tweeted: I'm a leader, yall on some followin s***... coming in dis game on some modelling s***, quoting lyrics from Lil Kim/Mob Deep's Quiet Storm remix.

There are multiple reports and speculations that Rihanna and ex-boyfriend have been meeting in secret. There also reports claiming that on her 24th birthday, Chris Brown was present too and they were apparently getting pretty close with each other in the party.

It certainly came as a surprise for Rihanna's fans to see her working with Chris Brown, who in 2009 physically abused the singer to the extent that her face got distorted. When she confidently walked out of the relationship, she was looked upon as an epitome of confidence and self-respect.

While Rihanna recently denied rumors of getting back with Chris brown at an interview for Jonathan Ross show in London, a representative for Brown has denied the rumors saying, He and Rihanna are just friends, the representative told ABC News. He's not cheating.

So if all the rumors are not true, then what is this fight all about Rihanna?