Chris Brown and Usher were reportedly embroiled in a heated argument just moments after Usher sang Chris happy birthday at his roller skating event.
Chris was celebrating his 34th birthday surrounded by celebrity pals, including Usher and fellow singer Teyana Taylor, at the Skate Rock City roller rink in Las Vegas.
The Go Crazy singer is reportedly close with Usher, but sources have claimed that an argument between the pair later led to a "violent scuffle" outside the event.
Eyewitnesses told TMZ that Chris had been attempting to talk to Teyana, who was sat on a bench outside the rink. For an unknown reason, she was ignoring the star.
The source claimed that Chris became angry and began yelling at her before Usher intervened, attempting to diffuse the situation and calm Chris down.
In the clip obtained by the publication, Chris can be seen directly talking to Usher and eyewitnesses claim that he began swearing at the Love in this Club singer.
While Chris was said to have left the venue with his entourage, Usher allegedly removed his skates and followed suit.
Sources at the scene claimed to have seen Usher go behind a string of charter buses that were parked outside and, after a short period of time, emerged with what appeared to be a bloodied nose.
Despite the alleged drama between the celebrities, no police report has been filed and all three parties involved – Teyana, Chris and Usher – have yet to break their silence on social media.
Hollywood Unlocked initially reported that Chris Brown was "noticeably intoxicated" when he had approached Teyana earlier in the evening, according to their sources.
The insider also claimed that Chris had been "disrespectful" towards her before Usher stepped in. He was then heard allegedly calling Usher a "coward."
News of an alleged fight between Chris and Usher comes as a surprise to fans who are well aware of the close friendship between the duo.
Last year, Usher brought Chris out at one of his Vegas shows and, in a clip circulating online, praised Chris for his hard work.
