The British singer - born Amelia Warner - was married to the Fright Night star for four months in 2001. However, she revealed that the pair never had a real wedding.
"We didn't actually get married - it's not actually true," Warner told The Sun. "I think we've been too polite to deny it.
"We had a ceremony on a beach in Tahiti that was by no means legal and we knew it wasn't. It was just a thing we did on holiday. We went shark feeding and then we did that. We booked them both on the activities desk at the hotel."
Warner went on to insist that the ceremony was not meant to be a private affair.
"It really wasn't this secret wedding that no one was invited to," she said. "It was lovely, it was silly, it was sweet but by no means was it a serious thing and I think my mum thought it was quite funny."
Farrell recently revealed that he was inspired to become an actor after seeing E.T.: The Extra-Terrestrial.
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Watch a trailer for Colin Farrell's Fright Night below: