(CNN) -- Singer Andy Williams has bladder cancer, is undergoing treatment and plans to return to performing in 2012, he said.
"You may have read or heard that I have bladder cancer. It's true and I'm currently undergoing treatment to deal with it," Williams said in a statement.
The singer also told fans at a concert in Branson, Missouri, Saturday night that he has cancer, a reporter who attended the concert told CNN on Sunday.
"But that is no longer a death sentence. People with cancer are getting through this thing," Williams said, according to Tyler Francke with the Branson Tri-Lakes News.
"They're kicking it, and they're winning more and more every year. And I'm going to be one of them," Francke quoted the singer as saying.
Williams, 83, shared the news during his Christmas Show at the Moon River Theater, which he founded in 1992, according to the theater's website. "Moon River" was one of Williams' most popular songs.
The description of Williams' Christmas Show on his website lists several guest stars, and notes that "due to health reasons, Andy may not make a live appearance in his Christmas Show."
In his statement, the singer said he plans to return to performing in 2012.
Attempts by CNN to contact the Moon River Theater for comment were not immediately successful.
Williams began his singing career as a child in a quartet with his three older brothers. He later got a regular gig on Steve Allen's "Tonight" show and then his own variety program, "The Andy Williams Show," in the 1960s.
CNN's Denise Quan contributed to this report.