Fawcett was at Bernstein's bedside when he died Sunday at Cedars-Sinai Medical Center from the effects of a stroke, The Los Angeles Times reported.
"There are no words to express how sad and devastated I am," Fawcett said in a statement. "I have lost one of my dearest friends and the industry has lost a giant."
After switching to personal management in 1975, he turned Fawcett into a superstar with her role in "Charlie's Angels" and her legendary swimsuit poster.
He was credited with securing a $2 million Lloyd's of London insurance policy on "Entertainment Tonight" anchor Mary Hart's legs and reportedly even paid women to throw their hotel room keys at singer Tom Jones.
Somers said she hired Bernstein after seeing what he did for Fawcett.
She told the Times she gave Bernstein all the money she made in the first six weeks of "Three's Company" -- but it turned out to be a good investment when he got her 55 magazine covers in the first year alone.
Bernstein married model Cabrina Finn underwater in 1993 on TV's "Lifestyles of the Rich and Famous," but they divorced two years later.
His survivors include a daughter, a sister and his mother.