The impressionist, who wowed the judges on last night's (April 20) show, spent the night with the Hollywood actor after meeting him in a London bar in 1999, The Sun reports.
She was a hostess on The Generation Game when she went back to DiCaprio's suite at the Metropolitan Hotel. Although she later claimed they didn't sleep together, it ended her relationship with childhood sweetheart Sacha Tropper.
She is quoted as saying at the time: "I'm so sexy no one man can satisfy me. I'm a friendly girl and I can't say no to anyone! I like to make eye contact with a guy and if he gives me that little smile back I know I'm in there."
Lewis, who appeared on The Big, Big Talent Show in 1996, last night called the story "old news".
She also revealed that she once met Simon Cowell in a club, joking that she wants to go on a date with him without her husband.
Watch Francine Lewis on Britain's Got Talent below: