Michael Buble's son is reportedly suffering from liver cancer.
The Canadian crooner and his wife Luisana Lopilato announced last week that three-year-old Noah had cancer, and the youngster was diagnosed after having a liver biopsy following an initial check-up at a clinic in Buenos Aires, Argentina, after the 29-year-old actress took him for a consultation because he had a high fever.
Argentine magazine Gente reported: "She took her son to the Otamendi Miroli Hospital in Buenos Aires because he had a high fever.
"After an exhaustive examination, they ruled out mumps and suggested two possibilities, a throat infection or mononucleosis.
"To rule out the second possibility they had to carry out a battery of tests which included an abdominal ultrasound.
"On October 27, after a throat swab, they confirmed he had a throat infection and not mononucleosis but the ultrasound had detected a liver problem.
"The doctors told Luisana, 'He has a stain on his liver, but it's not got different tones and therefore it's probably benign but we have to continue with the tests.' "
According to the publication, Michael, 41, who was working in London, urged his wife to seek a second opinion in Los Angeles, so his spouse, Noah, their other son Elias, nine months, and Luisana's parents, flew to the US to see another doctor.
Luisana's sister, Daniela, told Gente: "It was there they discovered something wasn't right.
"We have very good specialists but for personal and family reasons, Michael and my sister decided to fly to the States."
Noah is believed to have begun a four-month course of chemotherapy and may need surgery afterwards to remove the tumour, but his chances of beating the disease are 90 per cent.
Daniela added: "If God wanted it to be discovered that way, it's because he wants to save Noah.
"Cancer is a horrible illness but we have faith in Noah being able to overcome this.
"We know he will. The time to start a long and very difficult treatment has come but it's got to be done.
"They say children are normally strong to put up with chemotherapy and my nephew is a warrior."