NOFX fan kicked in the head by Fat Mike allowed on stage

The Sydney stagecrasher who was kicked in the head by NOFX singer Fat Mike on Wednesday has been allowed to take the microphone at their concert last night.

Alex Medak was allowed onto stage on the Enmore Theatre and joined the band in singing one of their songs at the Enmore Theatre.

Two days earlier his appearance on stage was far less appreciated.

The eager fan was elbowed in the face by Fat Mike as he approached the lead singer on Wednesday.

As Medak recoiled Fat Mike then kicked him in the head.

Fat Mike quickly apologised on Twitter for lashing out.

"I'm sorry too Alex, I was in terrible pain all night. When you grabbed me by the neck I defensively reacted…offensively," he wrote.

"Alex, if you go to the show on Friday I'll buy you a beer. Just don't throw it at me alright?"

Fat Mike joked about his stage behaviour last night, telling the crowd he was wearing "steel-capped clown shoes".

Medak is himself the bassist for a Sydney punk band called Sungriever.