Jane Fonda's Best Actress Oscar acceptance speech for this movie was one of the shortest in movie history: "Thank you...thank you very much, members of the Academy, and thank all of you who applauded. There's a great deal to say and I'm not going to say it tonight, I would just like to really thank you very much."

The scene with the psychiatrist was mostly ad-libbed. Pakula used just one camera and later said he should have used two as Vivian Nathan's reactions were much more interesting in the takes where the camera focused on Jane Fonda.

According to her autobiography, Jane Fonda hung out with call girls and pimps for a week before beginning this film in order to prepare for her role. When none of the pimps offered to "represent" her, she became convinced she wasn't desirable enough to play a prostitute and urged the director to replace her with friend Faye Dunaway.

When Jane Fonda asked her father for advice on what to say for her Oscar acceptance speech, he suggested: "There's a great deal to say, but I'm not going to say it tonight."

In the original script Bree's psychiatrist was male but Fonda felt in rehearsals, that the character would never open up to a man so she requested that the part be changed to a woman. Fonda requested to shoot the scenes with the shrink at the end of shooting so she would have already fully internalized the character of Bree.

Bree's apartment was built on a sound stage at a New York film studio where Jane Fonda could spend the night. The director even had a working toilet installed in the bathroom of the set. Jane contributed to decorating the apartment by deciding Bree would be a romance reader and have a cat. Jane remembered an actress from Lee Strasberg's private class that occasionally serviced John F. Kennedy, so she decided Bree had done this as well. A signed photo of Kennedy appears on the fridge in Bree's apartment.

Pakula wanted composer Michael Small not to play low notes in his score, because the audience already knows that it's scary.

When Peter Cable leaves in the helicopter, if you look carefully in the background you can see the original World Trade Center being constructed.

Moments after winning her Academy Award, Fonda told reporters in the press room backstage: "I'm not very happy about what the picture is saying to women, which is if you get a good shrink and a good guy everything will turn out alright, and I don't think that's true."

Sutherland and Fonda developed a nonexclusive romantic relationship offscreen which lasted until about June 1972. He was her date to the Oscars when she won Best Actress for this movie.

The first installment of what informally came to be known as Pakula's "paranoia trilogy." The other two films in the trilogy are The Parallax View (1974) and All the President's Men (1976).

Bree's audition piece is from Saint Joan by George Bernard Shaw.

According to Donald Sutherland, the time the lighting took up was immense. The actors rehearsed usually from 7 to 9 AM, then returning to their trailers and usually waiting for noon or 1 PM before shooting started.

Klute was only the second film score for Michael Small, who said that Pakula took a big risk here to work with an unknown composer.

Barbra Streisand turned down the role of Bree Daniels, which Jane Fonda eventually played.

Warner Bros. wanted to remove both Jane Fonda and Alan J. Pakula from the project at one time before shooting started, but it did not work out as most people turned the studio down and so they came back to their decision.

Composer Michael Small said that Pakula referred to the main theme of the score as "the siren call".

Future film star Sylvester Stallone made an appearance as an extra in "Klute."

Film debut of Rosalind Cash.

Film debut of Veronica Hamel.

The first of two best actress Oscars for Jane Fonda.

The film was part of a cycle of 1970s conspiracy movies. These included: Executive Action (1973), Klute (1971), Chinatown (1974), Cutter's Way (1981), Telefon (1977), Winter Kills (1979), The Conversation (1974), The Parallax View (1974), Three Days of the Condor (1975), The Domino Principle (1977), Good Guys Wear Black (1978), Twilight's Last Gleaming (1977), Hangar 18 (1980), Capricorn One (1977), and All the President's Men (1976). Blow Out (1981) would follow in the early 1980s.

The micro tape recorder is a M-75B from Electro Data Inc. It was first manufactured in secret for the CIA, where it was designated the UMY-25. It was declassified in the mid sixties, with EDI manufacturing them commercially from 1966 to 1967. It was designed to be durable, with a body made of cast aluminum. It was a stereo recorder, which made it possible to record things in two locations simultaneously. Its features included auto stop, fast forward and rewind. This was controlled by moving a small metal bar between the reels at the edge of the mechanism. The audio quality was passable but the pitch tended to waver, due to the tendency for the rubber tape roller to wear unevenly. The technical successor to this was the Nagra SNN, which was slightly larger but with much more sophisticated design and very high quality sound, which made it useful in the pre-wireless days of audio for feature films. The one advantage of the EID M75B was a motorized fast forward and rewind. In contrast, the SNN had a fold-out hand crank for rewinding.

Included among the "1001 Movies You Must See Before You Die", edited by Steven Schneider.

Final film of Vivian Nathan, who died in 2015.

The song "Wings of Desire" (1992) by Strawpeople, later made famous in the Nicole Kidman movie To Die For (1995), features sound clips of Bree talking.

Jane Fonda and Donald Sutherland would later appear in Steelyard Blues (1973).

Film debut of Charles Cioffi along with Shaft (1971), and in fact both films were released on closer dates (but Klute beat the other film for just two days). Both were released on June 1971.

Roy Scheider and Anthony Holland would later appear in All That Jazz (1979).

Donald Sutherland and Charles Cioffi would later appear in Shadow Conspiracy (1997).

This film is part of the Criterion Collection, spine #987.

French visa # 36491.

Jane Fonda said that she had to throw up while preparing for the scene where Bree goes through photos of dead prostitutes to identify her friends. She actually had gone to the city morgue too and it came as a great shock.

Although Fonda had planned on playing scared for the scene with the murderer (played by Charles Cioffi), when she heard the tape recording of the call girl about to be murdered and the fear in her voice, she unexpectedly started crying.

Body count: 4.