Legendary singer Andy Williams, who is best known for his hits Moon River and Can't Take My Eye Off You, has been diagnosed with bladder cancer.

Williams, 83, reportedly met with specialists at MD Anderson Cancer Center in Texas last month and has begun a three-week chemotherapy course. He started on Oct. 31.

Andy got the diagnosis of invasive bladder cancer very recently, a source told the National Enquirer. That means his cancer has invaded the lining of his bladder, but doctors weren't sure yet whether it had spread to other parts of his body.

The source also said that If the chemo shrinks the tumors, doctors will surgically remove An­dy's bladder.

Williams, who is also known as The Golden Voice, has a Christmas show this year.

He first recorded as a solo artist in 1953 and has released 18 gold and three platinum-certified albums over the next half-century.

Watch Williams perform Moon River below: