The rejected singer faced Simon Cowell and fellow judges in the audition room on numerous occasions. Most notably, her angry family demanded an explanation from the music mogul when he criticised her vocal ability.
Celebrity Juice star Lemon was signing copies of his new book The Rules: 69 Ways To Be Successful, in which he promises to "reveal the 69 rules of being a succ-sex" with the "bang tidy lasses".
Lemon also got to grips with another female fan, who had him sign her backside.
Comedian Leigh Francis will film a pilot episode for new ITV1 series Keith Lemon Kisses It Better later this month.
Keith Lemons's The Rules: 69 Ways to Be Successful is out now.
Watch a clip from the latest episode of Celebrity Juice below: