Country star Brad Paisley and his wife Kimberly Williams have revealed they were the victims of an online hoax.

Paisley told Nightline he received an email from a stranger claiming her daughter was dying from neuroblastoma, a cancerous tumor that generally occurs in infants and children and develops on nervous tissue.

Kimberly said, "She said that her daughter had begged her to get in touch with me… it sounded very sort of real. But she wasn't dying to get a hold of me. You know, that was kind of the beginning of the manipulation."

Kimberly and Brad immediately responded and talked to the woman, who claimed to be the mother of the child the couple saw in photographs. One night, Paisley sang Amazing Grace over the phone for the child. He said, "You're singing to someone's dying kid. And in the middle of it, there's no way that's not real. How can that not be real?

When the child "died," the mother quickly changed her tune. After refusing to offer an address to a funeral home the couple could send flowers to, the woman became hostile and wrote, "I don't need you to pray for me. Doesn't seem like god hears much of anything these days."

Kimberly tells Nightline of the sudden change, "Every red flag went up that I couldn't ask a simple question."

The photos Brad and Kimberly received turned out to be photos of other children suffering from the deadly affliction. Brad said, "That's the sickest part about this to me. 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."

The Nightline investigation turned up several other celebrities who became victims of similar hoaxes, apparently aimed at either getting money or personalized mementos from the stars.