Edward (Richard Gere) snapping the necklace case down on Vivian's (Julia Roberts) fingers, was improvised by Gere, and Roberts's reaction (laughter) was totally natural. The filmmakers liked it so much, they decided to leave it in.

*

The opera Richard Gere takes Julia Roberts to is La Traviata, which is about a prostitute who falls in love with a wealthy man.

*

During the lovemaking scene, Julia Roberts got so nervous a visible vein popped out of her forehead. Director Garry Marshall got into bed with Julia and Richard Gere. Marshall and Gere massaged her forehead until the vein disappeared. Julia also broke into hives and was given calamine lotion until they were finally able to shoot the scene.

*

The red coat that Vivian wears was bought for $30 from a movie usher in the street shortly before filming.

Sandra Bullock turned down the role of Vivian.

*

Richard Gere started off much more active in his role, but Garry Marshall took him aside and said "No, no, no. Richard. In this movie, one of you moves. And one of you doesn't. Guess which one you are?"

Burt Reynolds was offered the role of Edward Lewis but declined. He jokingly said on the Piers Morgan show in 2012 that after he saw the film and the love-making scenes with Julia Roberts, that he made a mistake in not taking the part.

*

The film's budget was not limited, therefore producers could acquire as many locations as possible for shooting on their estimated USD 14,000,000. The majority of the film was shot in Los Angeles, California, to be specific, in Beverly Hills. The escargot restaurant scene was filmed at the Rex, now called Cicada. Filming of the Beverly Wilshire Hotel lobby interior was shot at the now torn-down Ambassador Hotel. Filming commenced on July 24, 1989, but was immediately plagued by countless problems, including issues with space and time. This included Ferrari and Porsche, who had declined the product placement opportunity of the car Edward (Richard Gere) drove, because they did not want to be associated with soliciting prostitutes. Lotus Cars UK saw the placement value with such a major feature film. This gamble paid off as Esprit sales tripled between 1990 and 1991. The company supplied a Silver 1989.5 Esprit SE, which was later sold. The film's primary shooting was completed on October 18, 1989.

*

According to the DVD director's commentary, the piano key sounds that are made during the lovemaking scene on the piano had to be dubbed in because the actual keys that were randomly hit by Julia Roberts and Richard Gere as they did the scene made such a discordant sound that it was unusable in the actual movie.

Ralph Bellamy's final movie.

Director Garry Marshall shares a fear of heights with Richard Gere's character, Edward Lewis.

*

Christopher Reeve was originally considered for the Edward Lewis role. Denzel Washington and Daniel Day-Lewis were also considered.

*

Demi Moore turned down the role of Kit.

*

When Stuckey slams the door to his car they actually had to replace it, because the window broke.

*

Albert Brooks and Sylvester Stallone turned down the role of Edward Lewis.

*

In the dinner scene when Vivian flings the snail across the room, the waiter says, "It happens all the time." Garry Marshall cast the same actor The Princess Diaries years later and gave him the same line.

*

According to an interview in 2009, director Werner Herzog was approached by Richard Gere to direct the film when it was still a dark drama. He politely declined.

Daryl Hannah turned down the part of Vivian as she felt it denigrated women.