Carol Connors -- the legendary songwriter -- is telling all about her fame ... breaking it down in a new book and accompanying documentary.

Connors -- who's rubbed elbows with some of Hollywood's brightest stars -- recently released her new book "Elvis, 'Rocky' & Me" just recently ... and, TMZ can reveal she's also got a documentary coming out about her under the same title.

CC -- who skyrocketed to fame with her hit track "To Know Him Is To Love Him" written by infamous music producer Phil Spector -- will double down on the revelations in her book and tell her full story on-camera.

Connors will touch on shacking up with Elvis Presley for more than a year after he wanted to meet her following the success of 'To Know Him' ... and, she'll also touch on how she wrote "You Loved My Night Away" on the very night he died.

Carol's got Spector stories too ... including one tense interaction where she claims Phil slammed her up against a wall and threatened to kill her if she ruined his song.

But, no profile of Connors would be complete without diving into how she wrote the lyrics for "Gonna Fly Now" -- the 'Rocky' series theme that's living on for generations.

In her career, Carol's secured two Oscar nominations, three Emmy and two Golden Globe nods -- though she never managed to take one home. She's also got stories about Steve McQueen and O.J. Simpson ... whose trial she testified at.