(ABC News) -- In his number-one single "Online," country music star Brad Paisley sings about the perils of online relationships.
"I work down at the Pizza Pit and I drive an old Hyundai," the lyrics go. "Online I'm out in Hollywood. I'm 6'5" and I look damn good. I drive a Maserati, I'm a black-belt in karate."
Brad Paisley and his wife, "Nashville" actress Kimberly Williams-Paisley, recently experienced first-hand the dark side of online communication as they were drawn into an elaborate hoax that started with an email from a total stranger. A mother said that her daughter was dying of a neuroblastoma, a type of pediatric cancer that is often fatal.
"She said that her daughter had begged her to get in touch with me," Kimberly said. The email went on to say that Carrie, the mother, had forgotten about her daughter's request in the midst of everything else going on it their lives.
"So it sounded very sort of real," Kimberly said. "But she wasn't dying to get a hold of me. You know, that was kind of the beginning of the manipulation"
Over the next 10 days, Kimberly and the mother communicated with dozens of emails, phone calls and texts. Kimberly received photographs of the girl, named Claire, along with pictures of journal entries and recordings of songs that the girl had supposedly sung for Kimberly.
Brad Paisley, who is co-hosting Thursday's CMA Awards on ABC, also got on the phone and sang "Amazing Grace."
"You're singing to someone's dying kid," Brad said. "And in the middle of it, there's no way that's not real. How can that not be real?
But the story started to unravel after "Claire" died and the mother would not provide an address for the Paisleys to send flowers for the funeral. Then the mother wrote an indignant email: "I don't need you to pray for me. Doesn't seem like god hears much of anything these days."
"I had a physical reaction," Kimberly said. "Every red flag went up that I couldn't ask a simple question."
It turns out that the photos of the sick girl had been lifted from the blog of a real girl in Southern California who had neuroblastoma.
"That's the sickest part about this to me," Brad said. "That is the part that when I start to talk about that, that's when I get really mad. That there were real kids, that there were real photos involved."
It turns out that the Paisleys are not the only celebrities who were scammed. During the course of a year-long investigation, "Nightline" has learned of at least a dozen others who heard eerily similar sob stories, including the band Little Big Town, the reality television star Kate Gosselin, "Wipeout" hosts John Henson and Jill Wagner, members of the Dallas Cowboy Cheerleaders, and singers Mandisa, Natalie Grant, Francesca Battistelli and Carmen Hope Thomas.
"When I spoke to this woman she said she was the mom of a little girl and that her heart was breaking as she was watching her only daughter die," Natalie Grant said in a video statement to "Nightline." "We all were devastated by it and it's so disturbing that someone was claiming the identity of a little child with cancer and tried to pass it off as her child."
For more on what happened to the Paisleys and the other celebrities, and what happened when "Nightline" tracked down the person responsible at a campground in Wyoming, tune in to a special edition of "Nightline" Wednesday, Nov. 6 at 12:35 a.m. ET.