Tyler died unexpectedly in a hospital in Portugal after an illness, according to a statement posted on her official website.
She had been hospitalized in May following emergency intestinal surgery and was placed in a medically induced coma before later regaining consciousness.
Born Gaynor Hopkins in Skewen, South Wales, Tyler rose to international fame in the late 1970s with "It's a Heartache," a global hit that showcased the husky voice that became her trademark after surgery to remove vocal cord nodules.
Her debut album, The World Starts Tonight, was released in 1977, followed a year later by Natural Force, which featured "It's a Heartache."
Her biggest success came in 1983 with "Total Eclipse of the Heart," written by Jim Steinman and released on the album Faster Than the Speed of Night.
The power ballad topped charts around the world and became one of the defining songs of the decade. Steinman later adapted it for the stage musical Tanz der Vampire.
Tyler followed that success with "Holding Out for a Hero," recorded for the soundtrack to the 1984 film Footloose, and continued to score hits across Europe.
She also recorded duets with fellow Welsh singer Shakin' Stevens and enjoyed renewed popularity in German-speaking countries during the 1990s through her collaboration with producer Dieter Bohlen.
Later in her career, Tyler worked with musicians including Robin Gibb of the Bee Gees, represented the United Kingdom at the 2013 Eurovision Song Contest with "Believe in Me," and continued recording and touring.
Her 2019 album, Between the Earth and the Stars, featured collaborations with Rod Stewart and Cliff Richard, while The Best Is Yet to Come followed in 2021.
Tyler performed regularly in Poland throughout her career, most recently in December during her "40 Years Total Eclipse of the Heart" tour.
She was appointed a Member of the Order of the British Empire (MBE) in 2023 for services to music.
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Source: BBC, Reuters, IAR, PAP, TVP Info