Denise Van Outen and Lee Mead were dating for months before she got together with the Any Dream Will Do winner, she has revealed.
But in an interview with the Sun newspaper Van Outen insists she did not act unprofessionally when working as a judge on the show, which Mead eventually won.
Critics have applauded Mead's work in the West End production of Andrew Lloyd Webber's Joseph and the Amazing Technicolor Dreamcoat and Van Outen spent much of her onscreen time clearly impressed by his talent.
At the time he was with long-term girlfriend Kerry Stammers, however, as Van Outen is keen to point out.
"I rarely spoke to Lee during the series. There is quite a divide between the judges and the contestants, you have to be professional," she said.
"Also, he had a girlfriend who was at the studio and I would never have gone there, I'm old fashioned like that. They were broken up for three months before anything happened between us."
Van Outen admits she was dumped by actor James Lance but says she bounced back well and is not bothered by Mead being seven years younger than her.
"He's a gentleman and so talented. We are very similar, were both from Essex and have working-class backgrounds," she said.