Midler announced Forrest passed away Friday night, tweeting ... "The great and beloved Frederic Forrest has died. Thank you to all of his fans and friends for all their support these last few months."

She continued ... "He was a remarkable actor, and a brilliant human being, and I was lucky to have him in my life. He was at peace."

Forrest's cause of death was not disclosed.

The Oscar-nominated actor first hit it big in 1979 when he scored the part of Jay "Chef" Hicks in the Francis Ford Coppola war movie classic, "Apocalypse Now."

That same year, Forrest was nominated for Best Supporting Actor for his role as Dyer in "The Rose."

He went on to perform in dozens of movies throughout the '80's, '90's and early 2000s, including "The Two Jakes," "One From The Heart," and "Falling Down."

Forrest was 86.