Did You Know?

Orson Welles was originally considered for the role of Inspector Wang but was unable to accept because he was appearing in a play in Italy.

Myrna Loy was originally offered the part of Dora Charleston (a role that was a spoof of the character that she had played in the Thin Man movies) but she declined, later stating that "it would have been ridiculous to have Myrna Loy doing Myrna Loy". She also stated that she didn't want her "ass pinched by David Niven".

It was while working on this film that Alec Guinness received the script for Star Wars: Episode IV - A New Hope. He read it between scenes in his dressing room.

Immediately after completing the film, Peter Sellers was so convinced it was going to bomb, he convinced the producers to buy back his percentage share in the movie, thus depriving himself of a cut of the profits with the film when it went on to be a hit.

Originally Katharine Hepburn was meant to play a character called Dame Abigail Christian (a spin on Agatha Christie). Hepburn dropped out after hearing Myrna Loy would not do the film. The character was changed to Dame Abigail Christmas, and Estelle Winwood took the role. After numerous re-writes Estelle became Nurse Withers to a new character, Elsa Lanchester's Miss Jessica Marbles.

An interview with writer Neil Simon in a DVD extra Murder by Death: A Conversation with Neil Simon has him reveal that he and director Robert Moore at one time wished to replace Truman Capote with a real actor in the part of Lionel Twain but ultimately this never eventuated.

Peter Sellers reportedly played a number of practical jokes on cast and crew during filming, including once calling Neil Simon up whilst imitating co-star Alec Guinness and demanding a re-write of a key scene in the middle of the night. Neither Guinness nor Simon was amused.

David Niven plays Dick Charleston, a role based on Nick Charles which was originated by William Powell in the Thin Man movies. This is the second time Niven has played a role originated by Powell, having also played the titular role in the remake of My Man Godfrey.

Although Nancy Walker and Estelle Winwood's characters are listed in the final credits as simply "The Maid" and "The Nurse", they are blatantly named during the film as "Yetta" and "Miss Withers".

Three memorable scenes from this movie ended up on the cutting-room floor: 1) The Charlestons narrowly avoid hitting Tess Skeffington; she's hiking back to her and Sam Diamond's car, with gasoline from a station five miles away. "Thank Heaven you saw me when you did," she says. Dick makes sure she's okay - "Keep to the side of the road," he advises her - then simply drives off and leaves her to walk. 2) Willie Wang - upon rejoining the others in the drawing room, after covering up Lionel Twain's corpse in the dining hall - has noticed something that none of the others did: Twain was clutching a note in his hand. Without bothering to read the note first, Willie gloats about how he is a better detective than his own father gives him credit for: "I'm sick and tired of being just your #3 adopted son. The $1 million goes to whoever solves the crime, and that could be me just as well as you!" Then Sam takes the note at gunpoint ("Better stand back, Tess; I don't want you to get hurt when the bullet comes out his other ear") and reads it ("'Please call dairy and stop deliveries of milk; Lionel Twain deceased.' So much for your clue, kid"). Willie sheepishly apologizes to Sidney. 3) Leaving Twain Manor at the end of the movie, the Wangs pass a vintage car en route to the same destination. It's driven by Sherlock Holmes and Doctor Watson. They ask directions, which Sidney gives them despite Willie's efforts to warn them it's a ripoff. Willie asks why his pop didn't tell them the truth. Sidney's reply: "Let idiots find out for themselves."