The 'Because I Got High' hitmaker was performing in Biloxi, Mississippi when a woman walked onto the stage and approached him, according to Billboard.
In the video footage of the incident, the hip-hop star is seen playing guitar when he suddenly turns and lashes out at the stage invader, who falls to the ground. Security guards then help move her away.
Afroman, real name Joseph Edgar Foreman, was later arrested by police outside the venue.
A representative for the rapper said, "This was a completely involuntary reflex reaction to people infringing on his stage space. It was uncharacteristic behaviour that was initiated by outside uncontrolled forces.