Alley died of cancer that was only recently discovered, her children True and Lillie Parker said in a post on Twitter.
He performed on 'Sing Along With Mitch' and was a teenage idol in Japan before spending 46 years on the iconic kids TV program.
The 'Phantom of the Opera' touring lead revealed earlier this year that he was diagnosed with stage 4 colon cancer.
No cause of death has been revealed.
Over a career lasting more than five decades, Mair served as a label boss, artist manager and cherished mentor.
He performed the flute on Henry Mancini's 'Peter Gunn,' the tenor sax for Tony Curtis in 'Some Like It Hot' and the oboe on Frank Sinatra's "It Was a Very Good Year."
"He was a beloved and devoted father, husband, son, brother and a proud Brooklyn representative," read a statement posted on Saturday (Nov. 26).
He played a major role in the careers of Barbra Streisand, Billy Joel, Dolly Parton and Cher, among others.
'She was a beautifully gifted soul whose legacy will live forever through her music and films,' her publicist said.
Released in the mid-1990s, “The Beatles Anthology” was an authorized, multimedia project.
