World-renowned singer Michael Bublé has announced that his three-year-old son, Noah, has been diagnosed with cancer.

In a joint statement with his wife Luisana Lopilato, Bublé urged his fans to pray for Noah's recovery.

"We are devastated about the recent cancer diagnosis of our oldest son Noah who is currently undergoing treatment in the US," the statement, posted on Facebook, said.

"We have always been very vocal about the importance of family and the love we have for our children. 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."

No details were given about the details of Noah's cancer.

Bublé and Lopilato also have a second son, Elias, who is nine months old.

The singer recently told ITV's Loose Women: "I had no idea how much I would love being a dad.

"That's it, that's all I care about... I love them too much probably, if there was such a thing. It's made everything else so insignificant".

He told E! News earlier this year that being a parent "is a massive blessing".

"It's allowed me to understand deeply that what I do for a living – creating music and art and getting to be a part of a fragrance or a movie – is my job. It isn't what defines me. What defines me is I'm Noah and Eli's dad."