1977 No. 1, Originally Recorded By Another Singer For A Film, Reached The Top 49 Years Ago Today

Nearly 50 years ago today, "You Light Up My Life" was the biggest song, ever, and it wasn't even meant for the person who made it a hit. Debby Boone's debut single entered the Billboard Hot 100 at No. 71 on September 3, 1977. At first, it was a modest coming out for the 20-year-old daughter of legendary crooner Pat Boone. But six weeks later, this dynamic epic had gone to the top of the chart and refused to come down.

"You Light Up My Life" spent 10 straight weeks at No. 1, breaking Elvis Presley's record for the longest time at the top of the chart with "Don't Be Cruel" in 1956. Boone's record-setting streak wouldn't be topped until 1992 when Boyz II Men's "End of the Road" ran for 13 weeks at the top spot. By that point, Boone was an established music superstar, with multiple albums, two more Hot 100 hits ("California" and "God Knows/Baby, I'm Yours," both reaching No. 50 and No. 74 in 1978, respectively), and a Grammy award for best new artist of the year.

This illustrious career was built on "You Light Up My Life," and it's wild that hers wasn't the original version. That honor belongs to Kvitka "Kasey" Cisyk, who recorded a version for the 1977 movie of the same name. It's her voice, not Boone's, heard at the end of the movie. 

Growing up as the child of singer and actor Pat Boone, it was practically fated that Debby would join the family business. So, she sang lead in the Boones with her three sisters (and part of the family band, the Pat Boone Family). Eventually, music executive Mike Curb encouraged Boone to go solo. "[He] brought over to our house a cassette recording of this song, saying, 'There's an opportunity for Debby to record this song for radio release. It's a theme song to a movie,'" she told HuffPost in 2017. "I don't even know what happened, but suddenly, my parents were excited."

The song was "You Light Up My Life," by Joseph Brooks. Initially, Pat and Shirley didn't want Boone to be a solo act, likely because she was rebellious as a teen. Boone listened to the song, and it didn't really excite her, but she couldn't turn down a chance to record her first solo record.

The success of "You Light Up My Life" resulted in Boone recording more of Brooks' work for the film's soundtrack and her album, much to her chagrin. "I didn't love the song "California." A lot of people did. I would never have chosen to record that song," she told HuffPost. "I had fun with it and other Joe's songs. If I had heard any of the demos on those songs, I probably wouldn't have said, 'Oh please, can I do this one?'"

Joseph Brooks wrote jingles, but he wanted to make movies, so he wrote, produced, and directed a low-budget film called "Sessions" starring Didi Conn. It ends when the heroine releases her first record — and it's a hit! But every major studio rejected the film, except Columbia — but they had no idea how to promote it. So, Brooks renamed it "You Light Up My Life," and decided the best way to market the film was to release the finale's ballad as a single.

Kvitka "Kasey" Cisyk had previously worked with Brooks on jingles, which is how she ended up singing the song in the film. Brooks said she refused to sign off on releasing it as a single; Cisyk claims he never approached her about a deal. Ultimately, Debby Boone — who sang in the same key as Cisyk — recorded her version. It became a massive hit and earned Brooks both the Grammy for song of the year and the Academy Award for best original song. Cisyk died in 1998 from breast cancer.