The short clip, which was posted online by a fan at the gig, shows Rihanna running past the front row of the crowd.
As she passed the audience, members of the crowd excitedly tried to grab her and Rihanna appeared to angrily lift the microphone before slamming it in a fan's face.
[Rihanna turns up two and a half hours late to concert]
She is then seen continuing with her performance.
Rihanna, 25, was performing in Birmingham when the alleged incident happened and it is thought to be the same concert that she turned up late to.
[Rihanna's topless tour photo censored by Dubliners]
The singer was reportedly two and a half hours late on stage after a night of partying with her new model BFF, Cara Delevingne.
The pair went out partying on Sunday evening, not leaving nightclub Boujis until 3.15am on Monday morning.
The incidents follow her recent performance in Twickenham which was panned by critics.
[PHOTOS of Rihanna's off-duty Diamonds World Tour wardrobe]
In one review, Rihanna was described as looking 'bored,' lackluster and 'dead-eyed'.
It's been a tumultuous time for RiRi who split with boyfriend Chris Brown (for the hundredth time,) and then saw him get back together with his ex girlfriend.
It was also reported that police were called to her home in LA after a trespasser was found on her property.
A pretty shocking video has emerged showing Rihanna appearing to hit a fan in the face with her microphone during the latest date in her Diamonds tour.
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