Hemingway had a strong friendship with Dietrich

They have been handed to the John F Kennedy Library and Museum in Boston, along with several early drafts of Hemingway's stories and poems.

The documents, donated by Dietrich's daughter Maria Riva, will be made public in 2007.

They consist of 30 letters, cards and other documents that Hemingway and his wife Mary wrote to Dietrich from 1949 to 1959.

I love you too you beauty, indestructible Ernest Hemingway to Marlene Dietrich

They also include drafts of three stories - Across the River and Into the Trees, The Good Lion, and The Story of the Faithful Bull - and two poems, First Poem to Mary in London and Poem to Mary.

Ms Riva's son, Peter, said the letters depicted a relationship that was more than friendship but fell short of physical romance.

They include lines like: "I love you too you beauty, indestructible... I love you very much and hope you are well and happy and try to maintain a little communication."

Ms Riva's son said: "You read these letters and you come to understand that theirs was a relationship of firm, fast friendship based on an experience of the world they lived in.

"They could bare their souls in a way that was unusual then, and probably still is today."

Hemingway became the second most-translated author in English after Agatha Christie with masterpieces such as For Whom the Bell Tolls, A Farewell to Arms and The Old Man and the Sea.

He committed suicide at the age of 61.