Ianto (Gareth David-Lloyd)'s death during the sci-fi drama's third series in 2009 sparked an outcry from some fans, but Barrowman said in an interview with The Windy City Times that a resurrection for the character is unlikely.
"I think we have moved on," Barrowman explained. "Torchwood creator Russell T Davies explains it better - he says we couldn't have transplanted the show in the States and brought the entire company with it. People had to die!"
Watch Ianto's death scene below:
Although a television return for Ianto appears doubtful, Lloyd recently reprised the role for the Torchwood: The Lost Files audio series.
Barrowman previously revealed that he would like to return to Doctor Who for the show's 50th anniversary in 2013.
Torchwood: Miracle Day airs on Fridays at 10pm on Starz in the US and on Thursdays at 9pm on BBC One in the UK.
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Watch John Barrowman talking to Digital Spy about Torchwood below: