This was originally intended as a project for Peter Sellers before his death in 1980.
Dudley Moore, who plays a orchestra conductor, did in fact shadow Academy Award winner Bill Conti, who wrote the film's musical score to actually learn the techniques used to a symphony orchestra.
In the film, it is mentioned that Dudley Moore was scoring a film starring his wife played by Nastassja Kinski. In fact, Moore did compose the score the film Six Weeks (1982) co-starring Mary Tyler Moore, which came was filmed a year prior to this one.
This is the second straight film that composer Bill Conti had written the score for in which Armand Assante was the star of the film and also takes place in New York. The other film was I, the Jury (1982), which was filmed in 1982 and this one was filmed in early 1983.