Miller, who worked as a photographer during the Second World War, as well as a fashion and celebrity photographer, lived at an East Sussex farmhouse where 60,000 images were found in the attic by her family after her death 35 years ago.
The collection includes portraits of personalities the US-born photographer met during her career, among them Clark Gable and Fred Astaire.
Also languishing in the loft were 20,000 vintage prints and contact sheets.
After spending years of collating and digitising the collection, the photographer’s family say they plan to release the first 3,000 images on a new Lee Miller image library website, on 23 April – what would have been her 106th birthday.
Miller’s son, Antony Penrose, said he hopes the archive will serve as a ‘valuable resource for publishers, researchers, picture editors and students worldwide’.
Penrose added: ‘I hardly knew my mother during her lifetime – our home, Farley Farm House, had been filled with magical, kind and wonderful people who I later discovered were the leading artists of the day.
But in this warm atmosphere my mother often seemed absent, event when present.
‘She was often away travelling and when she was home she was frequently stricken with the incomprehensible suffering of PTSD [Post Traumatic Stress Disorder] and its consequent alcoholism and depression.
‘She had been relentlessly self-deprecating about her life so I knew nothing of her multifaceted career as a supermodel, surrealist photographer and combat photojournalist.’
Penrose said the family plan to eventually make all 60,000 images available, along with those of Lee’s British husband Roland who, he said, ‘often gives an interesting insight into her, her iconic images and their circle of friends, as well as a relevant selection of work by other photographers in their circle, such as Miller’s father Theodore Miller’.
The family say the archive will be available to view at www.leemiller.co.uk