"Secret Love" is a song composed by Sammy Fain (music) and Paul Francis Webster (lyrics) for Calamity Jane, a 1953 musical film in which it was introduced by Doris Day in the title role. Ranked as a #1 hit for Day on both the Billboard and Cash Box, the song also afforded Day a #1 hit in the United States. "Secret Love" has subsequently been recorded by a wide range of artists, becoming a C&W hit firstly for Slim Whitman and later for Freddy Fender, with the song also becoming an R&B hit for Billy Stewart, whose version also reached the Top 40 as did Freddy Fender's. In the U.K., "Secret Love" would become the career record of Kathy Kirby via her 1963 remake of the song. The melody is based on the opening theme of Schubert's A-major piano sonata, D.664.

Doris Day first heard "Secret Love" when its co-writer Sammy Fain visited the singer's home and played it for her, Day being so moved by the song that she'd recall her reaction as being: "I just about fell apart". Day recorded the song 5 August 1953 in a session at the Warner Bros. Recording Studio (Burbank), overseen by Warner Bros. musical director Ray Heindorf. The day of the recording session for "Secret Love" Day had done vocal exercises at her home, then about noon — the session being scheduled for 1 p.m. — had set out on her bicycle to the studio. Heindorf had rehearsed the studio orchestra prior to Day's reaching the studio; upon her arrival, Heindorf suggested Day do a practice run-through with the orchestra prior to recording any takes, but acquiesced to Day's request that her first performance with the orchestra be recorded. Day recalls, "When I got there I sang the song with the orchestra for the first time ... That was the first and only take we did" — "When I finished Ray called me into the sound booth grinning from ear to ear and said, 'That's it. You're never going to do it better.'"

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