Sons of Anarchy actor Alan O'Neill dead at 47

Alan O'Neill, who starred as Hugh in Sons of Anarchy in seasons six and seven, was found dead by his girlfriend in the hallway of her Los Angeles apartment. Photo / Getty Images

Sons of Anarchy star Alan O'Neill has died at the age of 47.

The Irish-born actor was discovered by his girlfriend in the hallway of her apartment in Los Angeles early on Wednesday evening, local time.

According to TMZ, O'Neill — who starred as Hugh in the hit series in season six and seven from 2013 to 2014 — had been suffering from chronic heart problems and was a heavy smoker.

He also reportedly had a history of "alcohol and drug abuse".

While no official cause of death has been released, TMZ reports that "no foul play is suspected" and that his body will undergo an autopsy.

Before Sons of Anarchy, O'Neill made his acting debut in 1997 TV movie Ballyseedy, following it up with a run on 2001 miniseries Rebel Heart.

He also starred in Irish soap My Fair City and British crime drama series Inspector George Gently.

He appeared in Pierce Brosnan's 2016 thriller Urge and had a role in the yet-to-be-released horror film Charlie Lives: The Family's Return.

It's not the first time Sons of Anarchy has been hit with the shock death of one of its stars.

In 2012, actor Johnny Lewis died at the age of 28 when he fell off the roof of a Los Angeles building, shortly after murdering his elderly landlady Catherine Davis.