Alan O'Neil, a veteran actor best known for his role on the final two seasons of Sons of Anarchy, was found dead on Wednesday night.
He was 47 years old.
According to TMZ, O'Neil's body was found in the hallway of her Los Angeles apartment this week, with all appearances indicating that he died very suddenly.
The actor reportedly had a history of heart problems and was also a heavy smoker.
Moreover, TMZ reports, O'Neil struggled over the years with alcohol and drug abuse.
An autopsy will be conducted at some point in the near future to determine cause of death, but law enforcement sources say no foul play is suspected at this time.
A veteran actor who has made a living in this industry since the 1990s, O'Neill is likely best known to American audiences for the role of Hugh on the aforementioned FX hit.
He portrayed this excommunicated member of the IRA for seven total episodes and even appeared on the series finale in 2014.
However, O'Neil's longest run on a series took place in Ireland's Fair City, on which he portrayed a main character named Keith McGrath.
He had just been cast in a horror film called Charlie Lives: The Family's Return prior to his tragic passing.
"My good friend Alan O’Neill died today....we worked together on The Sons Of Anarchy...my condolences to his family," actor Timothy V. Murphy Tweeted in response to O'Neil's death this evening.
"So sad to hear of the passing of Alan O’Neill who played 'Keith' in Fair City," actor Seamus Power wrote, continuing:
"Always enjoyed working with him. Rest In Peace old pal."
"Thinking of him, his family and friends...and all his fans. Rest easy," added a fan on social media.
This very sad loss comes just one month after another Sons of Anarchy star, David Labrava, revealed on that his 16-year-old son, Tycho Spelis Chiusano, had taken his own life after battling depression.
“Never in a million years would I think I would be posting this," he wrote on Instagram in mid-May, adding at the time:
"This is my boy Tycho. He took his life a couple of days ago at 16 years old.
"He suffered from a depression we couldn’t see because he was a happy young kid. I am broken."
Elsewhere, back in 2012, Sons of Anarchy Johnny Lewis was found dead at age 28.