It's a sad day for Sons of Anarchy fans. Alan O'Neill, who played Hugh on Seasons 6 and 7 of the hit FX show, has passed away. The actor was only 47 years old. The sad news was reported on June 7, after his girlfriend found his body in her apartment's hallway after he died the night before, law enforcement sources tell TMZ.

No foul play is suspected in the case. While an autopsy has yet to be completed to determine the cause of death, Alan reportedly had a history of heart issues, and had been a smoker for a long time. He also reportedly battled alcohol and drug addictions in the past, which may also have contributed to his sudden and untimely death.

alan o'neill 2014, getty

Alan O'Neill, 2014.

Alan appeared in seven epsiodes of SoA over the course of 2013 and 2014. He played an excommunicated member of the IRA, and his last appearance on the show was in the series finale. While Hugh was his most famous role, he has been an actor since the 1990s. His longest run on a show was in Ireland's Fair City, in which he played a main character names Keith McGrath. Alan had just been cast in a horror film called Charlie Lives: The Family's Return when he passed away.

The devastating loss comes just one month after another SoA star, David Labrava, revealed on May 10 that his 16-year-old son, Tycho Spelis Chiusano, had taken his own life after battling depression. “Never in a million tears would I think I would be posting this," he wrote on Instagram. "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." Our hearts go out to the SoA family in this terrible time.