An 81-year-old Shania Twain “superfan” was invited onstage by the country music star during her set at the Lytham Festival in northwest England on Thursday, July 4.Octogenarian Ken Northall joined Twain, 58, onstage wearing a cowboy hat, and said his favorite song was “Don’t Be Stupid,” because of the music video.A representative of festival organizer Rhodes Media told Storyful that Northall “has been going to Shania shows for 25 years.”The company said it was aware of Northall’s fandom and arranged a television interview with him ahead of Twain’s show. Twain’s personal team saw the interview and invited Northall on stage, Rhodes Media said.During the show, Twain changed the lyrics of her mega-hit "That Don