The version of "Evergreen" during the recording studio scene is a live recording, filmed in a single take. This was done at the insistence of
Barbra Streisand: she hates doing lip sync work; she wanted to be able to have closeups during the scene (which would expose any flaws in lip sync); and she wanted a more "natural" feel to that version (as evidenced by the kissing and laughing).
Kris Kristofferson, however, was very reluctant about singing live on screen, and had to be talked into it. A more formal studio recording was used for the final credits and soundtrack album.
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