The new ten-part run, subtitled Miracle Day, will air on BBC One in the UK and on cable channel Starz in the US.
"Nothing will be toned down for Starz," Barrowman told Access Hollywood. "If anything, we're pushing the boat [out] a little bit more."
He continued: "We have the freedom in the UK to do a lot more things on... the main channels, [whereas in the US] you can only do it on cable. The thing that's great about Starz is that we can push the envelope a little bit more."
The actor also suggested that Miracle Day will appeal equally to long-term fans and new viewers.
"As a fan, you can to continue to watch the show," he explained. "It picks up where we left off and you can still follow along what's happening.
"But having said that, [for] the new people who are going to watch it, it's going to be a brand new thing for them. You will be able to start off with this series and feel like you're joining in at the right time, at the beginning of a new show."
Torchwood: Miracle Day will premiere in July on BBC One in the UK and Starz in the US.
> John Barrowman: 'Torchwood is bigger and better'
Watch the video interview with John Barrowman below: