Rihanna and Chris Brown Break Up over Drake AND Karrueche Tran? Songstress Texts Beau's 'Frenemy' at Grammys, Model Teases with Flirty Tweets

Are the controversial lovebirds Rihanna and Chris Brown officially broken up... again? According to several recent gossip reports they are... and it's all because of ex-flames Drake AND Karrueche Tran. It's hard to believe any of the rumors surrounding the infamous R&B couple at this point... but apparently the duo hasn't spoken since the Grammys. As U.K.'s The Sun reports, RiRi spent the majority of the evening texting Brown's ultimate rival and frenemy Drake. The "Don't Wake Me Up" crooner wasn't too pleased with that. Meanwhile, Brown's ex-lover and model Karrueche Tran has been sending out some rather suggestive tweets, teasing that she may be keeping her former beau company while RiRi is off in London promoting her new fashion line "River Island"... ah, so the drama continues!

Rihanna and Brown were spotted cuddling up together at the Grammys... but they haven't appeared together in public since then. Rumors have it that they both partied at the same L.A. nightclub last week, but didn't even acknowledge one another. And they definitely didn't celebrate Valentine's Day together. And here's apparently why...

"Chris and Rihanna had a big bust-up at the Grammys over Drake. She was messaging him and Chris saw and it didn't go down well. Since that night they have barely spoken and have been doing their own things," an alleged inside source tells The Sun.

As several fans may remember, over the summer the two headstrong singers had a rather heated physical exchange at a NYC nightclub, allegedly over Rihanna. At the time, Brown apparently sent Drake a champagne bottle, only to have it returned with a note stating that the "YOLO" rapper once hooked up with Rihanna. (Oh, rumors were also swirling that Drake even hooked up with Brown's other leading lady, Tran). So it's no wonder why Brown isn't the biggest fan of the "Headlines" crooner.

Meanwhile, Brown's former flame Tran has been stirring up some drama of her own. On Feb. 17, the model tweeted a picture of a gold Victorian ceiling tagged with the message, "Gnight." The image has since been deleted. No biggie... until MediaTakeOut points out the fact that Brown recently rented out a multi-million dollar mansion in Houston, Texas for the NBA All-Star weekend. The singer previously posted pictures of himself posing with friends in the mansion, which just so happens to flaunt the same golden ceiling decor as the one in Tram's photo... hmm...

Despite all the recent breakup rumors, the fact of the matter is that RiRi and Brown are both just very busy in their seperate careers right now. Just this weekend, Rihanna debuted her "River Island" collection at London Fashion Week, was allegedly attacked in a nightclub by a deranged fan who yelled at her for "taking Brown back," and was compared to the late Princess Diana on the cover of The Sunday Times. That's a lot to handle, never mind throwing a serious boyfriend into the mix! So what do Mstarz fans think about all the latest Rihanna (and Drake) and Brown (and Tran) buzz?