TORONTO -- Canadian crooner Michael Buble's oldest son, three-year-old Noah, has been diagnosed with cancer.

The Burnaby, B.C., native, who is married to Argentine actress Luisana Lopilato, made the announcement in a posting on his Facebook page on Friday.

"We are devastated about the recent cancer diagnosis of our oldest son Noah who is currently undergoing treatment in the U.S.," Buble wrote.

"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," he added in the statement. "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."

Buble and Lopilato have another son, Elias, who turns one in January.

The announcement comes during a busy time for the multiple Grammy and Juno winner, who recently released the album "Nobody But Me."

It was also recently announced that he would be hosting the Junos in April. It wasn't immediately clear whether the news would affect his hosting plans.