You must be told how shamelessly little I have to offer

Orson Welles and Joseph Cotten met in 1934, became good friends and ultimately worked together on a number of films, including Citizen Kane (1941), The Magnificent Ambersons (1942) and The Third Man (1949). In the summer of 1966, Welles was casting his forthcoming film The Immortal Story (1968) and, eager to work with Cotten again, asked his friend to participate. (Renowned French actress Jeanne Moreau, who had worked with Welles on The Trial (1962) and Chimes at Midnight (1965), had already agreed to star in the film.) 

Apparently Cotten wasn't very enthusiastic after reading the script, after which Welles tried to persuade him through a letter (seen below), even though he had very little to offer his friend ("If you should be tempted to comfort me by agreeing to this, you should realize that you’d be trapping yourself into ten day’s hard work for almost no money"). Cotten eventually declined and accepted a part in Norman Foster's Brighty of the Grand Canyon (1966). Welles had presumably wanted Cotten to play the role of head clerk Elishama Levinsky, a role that eventually went to Roger Coggio. In the end, Welles and Cotten never worked together again.

The Immortal Story, which runs just under an hour, is based on a short story by Karen Blixen and was first broadcast on French television, followed by a theatrical release in France and the US. It is the only colour film Welles ever made. Welles disliked colour cinematography, but he received financing for his project from the Organisation Radio-Télévision Française and part of the deal was that he would shoot the film in colour. (The colour cinematography by Belgian cinematographer Willy Kurant is, I think, one of the film's biggest assets, along with the captivating presence of Jeanne Moreau and Welles' clever use of Erik Satie's beautiful piano pieces.)

Source: Heritage Auctions

Above: Roger Coggio in the role of head clerk Elishama Levinsky (a role initially meant for Joseph Cotten), with Jeanne Moreau in the background; Welles himself played Levinsky's master, the rich merchant Mr. Clay. Below: Welles and Moreau on the set of The Immortal Story.