June 8 (UPI) -- Irish-born actor Alan O'Neill died in Los Angeles this week. He was 47.
Best known for his work in the TV shows Fair City, Sons of Anarchy and Inspector George Gently, O'Neill was found dead in the hallway of his girlfriend's apartment Wednesday night, TMZ reported.
"Alan was a great actor, great guy and loved by all that knew him," O'Neill's agent, Greg Meyer, wrote in an email, confirming the death to The Hollywood Reporter.
The cause was not immediately disclosed. TMZ said the actor had a history of heart problems, as well as alcohol and drug abuse, and was a heavy smoker.
"So sad to hear of the passing of Alan O'Neill who played "Keith" in Fair City. Always enjoyed working with him. Rest In Peace old pal," tweeted Seamus Power, his former co-star.
"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 wrote in his own message.