Celebrity chef George Calombaris has had his conviction for assaulting a teenage soccer fan at the A-League grand final overturned on appeal.

Calombaris, 39, was at the A-League grand final between the Melbourne Victory and Sydney FC at Moore Park on May 7 last year. As he stood on the sidelines, he exchanged heated words with a 19-year-old fan in the stands then punched him in the abdomen.

In September, a court heard Calombaris told the teenager, "you're a big-mouthed man you dodgy c---" before the punch was thrown.

A lawyer for Calombaris said he believed the fan had called his mother a "c---" first.