This is the shocking moment a drunk guitarist attacked a band manager onstage in the middle of a performance in Thailand.

Angry musician Wanchai Pakkawae, 30, lost his temper in front of the audience during a concert in Nakhon Ratchasima province on October 21.

Footage shows Wanchai playing normally before locking eyes with a band member and flipping him off. He smashed his guitar on the speakers and continued gesturing wildly to the bewilderment of his confused colleague.

The portly man then left the stage only to later return with his shirt removed and tackle the band's manager, Suppamat Donsiyonphet, knocking him off of the platform.

Suppamat fractured his knee and sustained bruises on his shoulder and hip.

With the audience stunned in awkward silence, Wanchai confronted crowd before they erupted into mocking cheers.

Following the incident, the band's performances for the remaining days of the festival were cancelled as organisers feared a repeat of Wanchai's violent behaviour.

Rattiya Ponsean, the band's lead singer, clarified that the guitarist was only a temporary member of the group.

Speaking to local reporters, she said: 'He is a freelancer who is currently filling in for our main member. Organisers can still hire us for performances.'

The concerned parties met again for mediation at the local police station, with a more meek and subdued Wanchai offering his apologies to the group.

He blamed the assault on alcohol, claiming he had been inebriated during the concert.

Local media reported both sides have reached a settlement without the guitarist receiving police action, but upon the request of those involved, they did not disclose how much Wanchai was paying for damages.