Sydney: A westerner pictured alongside Islamic State group fighters and dubbed by media as "Britain's white jihadi" is in fact a teenager from Australia who converted to Islam, a report said today.

A picture of the meek-looking youth, holding a rifle and sitting in between two jihadists with a black IS flag in the background, emerged on Twitter in late December. At the time the militant group, which has run rampant through swathes of Iraq and Syria, hailed his recruitment as "a major coup" with the British media dubbing him "Britain's white jihadi".