American singer Connie Francis, whose hits such as "Everybody's Somebody's Fool" and "Stupid Cupid" topped the charts in the late 1950s and 1960s, has died aged 87, her publicist announced on Thursday.

Born Concetta Rosa Maria Franconero, Francis had found renewed popularity in recent months as her 1962 song "Pretty Little Baby" went viral on TikTok and other video-sharing platforms.

She was hospitalised earlier in the month after experiencing severe pain and had undergone a hip treatment, according to a post on her official Facebook page.

"It is with a heavy heart and extreme sadness that I inform you of the passing of my dear friend Connie Francis last night," her publicist, Ron Roberts, posted early on Thursday on Facebook, without specifying a cause.

Though Francis's heyday faded after the 1960s, she continued to record and perform for decades.

When announcing her hospitalisation on July 2, she expressed regret about having to miss a planned Independence Day show.

The singer had publicly discussed significant struggles with her mental health, particularly following a 1974 rape in a New York motel and the murder of her brother in 1981.

She was married and divorced four times, and in 2022 announced the death of her partner of almost two decades, Tony Ferretti.

Born in Newark, New Jersey, to an Italian-American family, Francis shot to fame in 1958 with the release of "Who's Sorry Now."

She went on in the next decade to sell millions of records worldwide, with albums in multiple languages. (AFP)