Audrey and Holly are both such wonderful girls

In one of the interviews Lawrence Grobel conducted with writer Truman Capote between July 1982 and August 1984, as recorded in Grobel's book Conversations with Capote (1985), Capote said that Breakfast At Tiffany's (1961) was "the most miscast film [he had] ever seen." Capote, who had written the 1958 novella on which the film is loosely based, further said:

It made me want to throw up… And although I’m very fond of Audrey Hepburn, she’s an extremely good friend of mine, I was shocked and terribly annoyed when she was cast in that part. It was high treachery on the part of the producers. They didn’t do a single thing they promised. I had lots of offers for that book, from practically everybody, and I sold it to this group at Paramount because they promised things, they made a list of everything, and they didn’t keep a single one. The day I signed the contract they turned around and did exactly the reverse. They got a lousy director like Blake Edwards, who I could spit on!

Capote's choice for the part of Holly Golightly had always been Marilyn Monroe, who was also a good friend of his ("Holly had to have something touching about her... unfinished. Marilyn had that."). Capote said that Marilyn had really wanted the role, so much even "that she worked up two whole scenes all by herself and did them for [him]."

While Capote felt betrayed by the studio's decision to give the role to Audrey, it must be noted that the role had been offered to Marilyn first. Marilyn's drama coach Paula Strasberg, however, felt the part of a call girl was wrong for Marilyn and thus Marilyn declined. When Audrey was asked for the role, she wasn't eager to play it initially, also considering herself unsuited for it. It was director Blake Edwards who eventually convinced her to accept. (In the end, it proved to be Audrey's most iconic performance, for which she also received an Oscar nomination.)

Photo booth pictures of Truman Capote, Audrey Hepburn and Mel Ferrer in New York City, taken around 1956.

In the spring of 1960, it was announced that Audrey had been cast as Holly Golightly, with the shooting of Breakfast At Tiffany's to start in September of that year. On 17 July Audrey gave birth to her first child, son Sean by her first husband Mel Ferrer. To congratulate her on the birth of her son, Capote wrote Audrey the following letter from Spain where he was working on a new book. In the letter he also told her how pleased he was that she was going to do Tiffany's. Capote's words are in sharp contrast to his later statements about Audrey being totally wrong for the part. It's unclear whether his remark in the letter was a white lie (not wishing to burst his friend's happy bubble after she just had a baby?) or if he was simply less opposed to Audrey playing Holly than he would later claim. At any rate, this is not the only instance when Capote had expressed himself positively about Audrey regarding Tiffany's. At one point he had also said: "Audrey was not what I had in mind when I wrote that part, although she did a terrific job." (Indeed she did!)

Incidentally, Capote closes his letter with "Mille Tendresse", the last words Holly wrote to Fred in the novella. 

Source: Christie's

Transcript:

"AZ-ZAHARA"

PLAYA DE ARO

COSTA BRAVA,

Spain

23 July 1960

Dearest Audrey,

With two such parents, I'm sure it must be a most beautiful little boy, wicked-eyed but kindly natured. My life-long blessings on the three of you.

May I say, too, how pleased I am that you are doing "B.ATT." I have no opinion of the film script [written by George Axelrod], never having had the opportunity to read it. But since Audrey and Holly are both such wonderful girls, I feel nothing can defeat either of them.

I am spending the summer here (until end of Oct.), and then going somewhere in Switzerland- the point being that I am working on a new book, and plan to stay abroad until I've finished it.

Please give my love to Mel.

Mille Tendresse, 

Truman