The script tells us that, at the time of his death in 1942, John Barrymore had not worked in five years. Truth of the matter is that he had prominent roles in two films in 1939, two in 1940, and two in 1941, and at least four of them, Midnight (1939), The Great Man Votes (1939), The Great Profile (1940), and The Invisible Woman (1940), are quite notable and still shown today on cable television.
The film infers that Diana Barrymore's career ended as a result of the bad preview audience reaction to her first and only film and her refusal to go back and do retakes; actually, she had a leading role in six films over a two year period, and reviewers tended to be polite and complimentary, although not enthusiastic.
There's a scene involving a preview screening of the 1941 Humphrey
Bogart movie All Through the Night (1942), which Diana is supposed to have a part in. The results of the screening are negative, with the audience having particular dislike for Diana and leading Charlie Snow to declare the film a flop. In reality, Diana Barrymore was never a part of that film and it was a success at the box office, not a flop.
In the film, Diana Barrymore is under contract to the fictitious Charlie Snow and Imperial Pictures; actually, she was under contract to Walter Wanger, and all six of her films were released by Universal.
In actual life, Blanche Oelrichs aka Michael Strange, was the second of John Barrymore's four wives, the others of whom are talked about in Diana's book, but none of whom, apart from Strange, are even mentioned in the film.
Although the bulk of the story takes place in the early 1940's, all of the clothes and hairstyles worn by Dorothy Malone, Neva Patterson, and the other female members of the cast are strictly in the 1957 mode.