Irish actor Alan O'Neill, who appeared in hit US show Sons of Anarchy, has died aged 47, according to reports.
Best known for his portrayal of Hugh in the cult motorbike gang crime drama, O'Neill also appeared in Irish soap Fair City and several films.
The performer's manager Greg Meyer confirmed the actor's death to Variety.
Fellow Sons of Anarchy stars have paid tribute to O'Neill on Twitter.
Irish actor Timothy V Murphy, who played Galen O'Shay, said: "My good friend Alan O'Neill died today....we worked together on The Sons Of Anarchy...my condolences to his family."
US actress Kristen Renton, who played Ima Tite, said: "RIP sir... my you find peace now."
Irish actress Jenny Dixon, who worked with O'Neill on 2012 short film Invisible, said he was a "great friend who taught me so much".
She tweeted: "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."
O'Neill's career began in the 1990s, with several television appearances before his big domestic break on Fair City in 2006.
He appeared in the sixth and final seventh season of Sons of Anarchy, which ended in 2014, and most recently played the Captain in 2016 film Urge.
The actor was found dead at an apartment in Los Angeles on Wednesday night, according to TMZ.
No foul play is suspected in his death, with reports suggesting he had suffered health problems.