Rihanna and Chris Brown have split up again; the couple has gone their separate ways after spending four months together.

Rihanna was seen inside a Hollywood nightclub last weekend with only her assistant and security guard, no Chris Brown. Rihanna is currently performing in Los Angeles on her 'Diamonds' world tour, and left the club after spending an hour smoking inside.

The breakup allegedly stemmed from Chris Brown being photographed over the weekend with a blonde woman at the Playhouse Club in Los Angeles, sparking rumors that he was cheating on Rihanna. However, the waitress, Keisha Kimbell, has denied that anything happened between them.

22-year-old Kimbell told TMZ, "I am always Chris' waitress. I know him and am friends with his friends. Nothing has ever happened. I just work there. In the photos, he was handing me a bottle to drink out of. Of course people are going to twist it another way. I don't go for black guys."

"Whatever is going on between Rihanna and Chris Brown is between them. I'm not trying to be a home wrecker," she added.

Sources told TMZ that brief break-ups are nothing new for the on-again, off-again couple. They added that they expect the couple to be back together soon.

However, while Brown and Rihanna are broken up, Brown's ex-girlfriend Karrueche Tran may be interested in getting back together with the singer.

Tran and Brown broke up in October 2012 after they spent two years together. They allegedly broke up because Brown was still seeing Rihanna.

But despite their past difficulties, Tran still carries a flame for Chris Brown.

A source told HollywoodLife, "She would [get back together with Brown]. She likes him a lot. There's nothing like the first real love. They were together and there are still feelings there so yes, I think she would."

"She had a good time with him and he respected her and treated her good and he never lied to her. He was up front from jump so you have to respect that. He may have done some things that people on the outside judged him for, but Karrueche always knew what to expect," the source added.

Chris Brown doesn't have any bad feelings towards his ex, so perhaps there is a chance that they could rekindle their old romance.

Brown told DJ Sway Calloway, "We're cool man. I wish it could be better because of obvious reasons, but I think it's better to see her happy and successful. She still does the clothing line with me, so it's still a camaraderie between us."