Carol Vorderman had to call the police after she was tracked down by a fan who thought she was talking to him through his television.
The man began lurking around the Countdown studios when Carol co-hosted the Channel 4 show and the star was so concerned, she contacted cops.
During an interview for Piers Morgan's Life Stories, to air on ITV soon, she revealed: "I have had stalkers over the years. The police deal with it but it is very scary.
"One man kept turning up where we filmed Countdown in Leeds, which was scary. It was sad as he'd been sectioned and thought I was talking to him through the TV."
Carol is still upset about quitting the show in 2008 after a row with producers over money, and she is still grieving for her former co-host Richard Whiteley, who died after a heart operation in 2005.
She told Piers Morgan: "It still hurts very much. We worked together for 23 years. It was a total and utter joy to be with him."