Alan O'Neill was found dead in his Los Angeles apartment.
The Hollywood actor, 47, best known for his portrayal of Hugh in cult motorcycle gang drama 'Sons of Anarchy', died on Wednesday night.
Mr O'Neill, who had a history of chronic heart problems, also appeared in Irish film 32A and popular soap 'Fair City'.
The Irish actor is being commemorated by friends and fans who followed his career.
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. pic.twitter.com/8EnoRnwmLT
— Seamus Power (@MrSeamusPower) June 7, 2018
My good friend Alan O’Neill died today....we worked together on The Sons Of Anarchy...my condolences to his family @SonsofAnarchy pic.twitter.com/JTCwsWc6Kp
— Timothy V Murphy (@TimVMurphy) June 7, 2018
One of the first films I did & a privilege to act across from @AlanONeill19 .A great friend who taught me so much. Thank you for your kindness. So very sorry to hear of your passing. A great man, sadly missed. My thoughts & prayers to you & to your family😢🙏 pic.twitter.com/Kygj7pybWo
— Jenny Dixon (@JennyleeDixon) June 7, 2018
OmG...... few words rt now.......
Such a great and talented guy..... Rest in peace Mr
Alan O’Neill 🙏 #Hugh #SonsofAnarchy #Irish #Actor
you will be missed my brother🙏 pic.twitter.com/6Qxbp42kIn— Sean McNabb (@SeanMcNabbLA) June 8, 2018
Police investigating deemed his death as not being suspicious.