Michael Buble’s eldest son Noah is battling liver cancer and will have to undergo four months of chemotherapy, it has been reported.

Last week Buble and wife Luisana Lopilato shared that Noah had been diagnosed with cancer, but speaking to Argentinian magazine Gente, Luisana's elder sister Daniela confirmed that the three-year-old was battling liver cancer.

Michael BubleMichael Buble’s son Noah has been diagnosed with liver cancer

Daniela told the magazine that Noah has begun treatment after being diagnosed with cancer last week, following an initial examination in a Buenos Aires clinic.

“If God wanted it to be discovered that way, it’s because he wants to save Noah," Daniela told the magazine, according to The Mirror.

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“Cancer is a horrible illness but we have faith in Noah being able to overcome this.

“We know he will,” she continued. “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 enough to put up with chemotherapy and my nephew is a warrior.”

In a Facebook post last week Michael and Luisana first shared the devastating news of Noah’s diagnosis.

“We are devastated about the recent cancer diagnosis of our oldest son Noah who is currently undergoing treatment in the US. We have always been very vocal about the importance of family and the love we have for our children,” they wrote.

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“Luisana and I have put our careers on hold in order to devote all our time and attention to helping Noah get well. At this difficult time, we ask only for your prayers and respect for our privacy.

“We have a long journey in front of us and hope that with the support of family, friends and fans around the world, we will win this battle, God willing.”