Starz CEO Chris Albrecht has indicated that the sci-fi drama might not return for another season, following the conclusion of the ten-part Miracle Day.
"We've pushed the pause button now because we don't know what's happening," Barrowman told RTÉ Ten. "I would love to do a new series and I will play Captain Jack as long as they want me to play Captain Jack."
However, he added: "It's in limbo at the moment and beyond my control."
Barrowman also suggested that Torchwood could return as a feature film.
"I think that Torchwood, more so than [parent series] Doctor Who, lends itself to being a big film because it's more adult," he said.
Torchwood executive producer Julie Gardner recently admitted that the show's future is uncertain.
"I don't know if there will be more," she said. "It... has been across so many different channels and so many international audiences, across so many different story structures, and so many numbers of episodes. There's no single way forward for the show."
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Watch John Barrowman discuss the last series of Torchwood below: