Marlon Brando was sought for the role of Marc Antony but was attached to Mutiny on the Bounty.

Robert Stephens said in a radio interview that most of his part was deleted from the final print.

Hume Cronyn was originally signed to be on the film for 10 weeks. He stayed with the production for 10 and a half months.

Elizabeth Taylor became the first actress to earn a million dollars when she agreed to star in this film. Her overall take of seven million is equivalent to about 29 million in 2009 dollars.

Elizabeth Taylor had 65 costume changes for this film, a record for a motion picture. The figure is exceeded by Joan Collins, who had 85 costume changes in the TV miniseries Sins.

Elizabeth Taylor had met Richard Burton several years prior to their working together on the film; she had found him to be brutish and boorish. However, when Burton showed up for work on Cleopatra on his first day, it was with a hangover so severe that he had the shakes. Taylor had to help him around and administer to such basic needs as helping him drink a cup of coffee. This time, she found him to be very endearing.

Elizabeth Taylor reputedly threw up the first time she saw the finished product.

Elizabeth Taylor's contract gave her director approval. When Rouben Mamoulian resigned from the production, Taylor would only approve two men as possible replacements: George Stevens and Joseph L. Mankiewicz. Stevens was already at work on The Greatest Story Ever Told.

Elizabeth Taylor's contract stipulated that her million-dollar salary be paid out as follows: $125,000 for 16 weeks work plus $50,000 a week afterwards plus 10% of the gross (with no break-even point). When the film was restarted in Rome in 1961, she had earned well over $2 million. After a lengthy $50 million lawsuit brought against Taylor and Richard Burton by 20th Century Fox in 1963 and a countersuit filed by Taylor, the studio finally settled with the actress in 1966. Her ultimate take for the film was $7 million.

Joseph L. Mankiewicz hoped that the film would be released as two separate pictures, "Caesar and Cleopatra" followed by "Antony and Cleopatra." Each was to run approximately three hours. 20th Century-Fox decided against this, and released the film we know today. It runs just over four hours. It is hoped that the missing two hours will be located and that one day a six-hour 'director's cut' will be available.

Joseph L. Mankiewicz originally wanted to have either Laurence Olivier or Trevor Howard as Julius Caesar. Olivier had full theatrical commitments due to running the National Theatre of Great Britain, whilst Howard was caught up in the protracted filming of Mutiny on the Bounty.

Joseph L. Mankiewicz told Martin Landau that he had enough cut footage to make another movie called "The Further Adventures of Octavian and Ruffio".

Joseph L. Mankiewicz was never proud of this film and only made it out of sufferance for his friend, Elizabeth Taylor. At one point he even tried to have his name taken off. He was however paid $3 million for making it, a then unheard of sum of money for a director.

Martin Landau learned Italian during the shoot.

Martin Landau was booked to play Euphranor, but when they could not find anyone to play Ruffo, Landau was recast

Martin Landau was cast after Joseph L. Mankiewicz admired his performance in North by Northwest. Mankiewicz called up Alfred Hitchcock to ask him if he could act.

John Hoyt, who plays Cassius, the chief conspirator against Julius Caesar, played the role of Decius Brutus, another of the conspirators, in both Orson Welles's 1937 Fascist-themed stage production of Shakespeare's 'Julius Caesar', and in MGM's more traditional 1953 film version of the play.

Rex Harrison had a clause in his contract stipulating that whenever a picture of Richard Burton appeared in an ad, so would his. A large sign was put up on Broadway showing only Burton and Elizabeth Taylor. After Harrison's lawyers complained, the studio fulfilled the contract by placing a picture of Harrison on one corner of the billboard.

Darryl F. Zanuck, in principle, did not object to Joseph L. Mankiewicz's idea to have 2 3-hour movies. However, he knew the public was obsessed with the Elizabeth Taylor-Richard Burton affair and would not show up to see the first part in which Burton did not appear. Thus, the two parts were edited into one single movie.

Michael Hordern said on a chat show he was under contract for 18 months