Hip-hop rivals Chris Brown and Drake turned a New York City nightclub into a war zone that sent four innocent bystanders to the hospital early Thursday when they started a brutal brawl over the pop music diva Rihanna. 

Witnesses say the two recording stars started fighting after Chris Brown sent Drake a bottle of Champagne as a peace offering. Drake reportedly sent the bottle back with a note: 'I'm f****** the love of your life, deal with it.'

Chris Brown, 23, dated Rihanna until she dumped him after he savagely beat her on the eve of her performance at the Grammy Awards in 2009. After their breakup, the beauty from Barbados was romantically linked with rapper Drake. 

Reports indicate Rihanna, 24, is in the process of getting back together with Chris Brown. 

The New York Police Department is investigating the fight, which broke out at Club W.i.P in the SoHo neighborhood of Manhattan. 

A spokesman said investigators believe Chris Brown, his bodyguard and a woman with him was trying to leave the club about 4am when they were confronted by five members of Drake's posse.  As they were squaring off, someone -- police don't know who yet -- threw a bottle.

A source told the New York Post: 'They were on opposite sides of the room, Drake went over to the middle of the club to talk to someone, then words were exchanged with Chris and his entourage. The source said someone from Drake's entourage, possibly the singer himself, threw a bottle.

'Once the bottle was thrown, all hell broke loose and there were more bottles thrown.'

The fight allegedly kicked off as the last song was playing, just before 4 a.m.  Police were already at the scene because it was closing time and that they 'were on it in seconds and began getting everyone out of the club.'

The New York Police department confirmed to the Global Grind that the two singers' crews got into a fight at Manhattan nightclub - 5 people were injured in the melee including Chris' bodyguard who suffered a serious cut to the head, two other men and two women suffered minor cuts. At least three were hospitalised.

Police were looking at surveillance footage and talking to patrons who witnessed the melee. No arrests have been made and no complaints filed.