The All Rise singer - who is taking part in the new series of Channel 4's social media reality showThe Circle - revealed he had £5k stolen from his account after replying to an email he believed to be from the government tax authorities.
James, 42, said: "There are lots of catfishes out there, you can never really trust anybody.
"I've been stung before. I got an email from a fake HMRC telling me about a tax rebate that I had to give my details. I didn’t think and just handed it over. And then my accountant was like, 'HMRC will never ask for your account details. They have them. You don't need to do that.' And I was like, 'S***, what have I done?' and then I looked in my account and they had cleared me out. They took about five grand."
He added: "Thankfully, the bank knew. I had to send in the emails that I had, and I got my money back."
The former boyband singer is among the celebrity line-up for the latest series of reality show The Circle - which sees contestants interact with each other online and therefore choose how much of their true selves they present to one another.
James said: "I want to go in with a bit of a blank canvas. I want people to think that potentially I might not be who I am because then I think you can play that to your advantage. But I also want to go and be me."
The bisexual singer - who has a 16-year-old daughter Tianie from a relationship with ex-girlfriend Claire Grainger - revealed he has spent lockdown living with his mum.
He said: "It's just nice to get out of the house and have a little bit of me time."
Other celebrities taking part in the new series - in aid of Stand Up To Cancer - include Loose Women Kaye Adams and Nadia Sawalha, drag queen Baga Chips, Geordie Shore star Charlotte Crosby and EastEnders star Denise Van Outen.
The six-part celebrity series will air on Tuesday 9 March 2021.
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