GRENOBLE, France (AFP) – Veteran US singer Al Jarreau was in a stable but "worrying" condition in a French hospital on Friday after falling ill just before he was due to go on stage, health officials said.

Jarreau -- whose jazz, pop and soul songs have won him seven Grammy awards -- was about to begin a festival concert late Thursday in the Alpine town of Barcelonette when he was taken ill with an unduly rapid heart beat.

The 70-year-old was treated on the spot for a couple of hours but was later flown by helicopter to a hospital intensive care unit in nearby Gap where he was admitted with breathing and heart problems, hospital staff said.

The hospital said he was in a "critical" condition when he arrived but on Friday Pierre-Yvan Simonoviez told reporters that "his condition stabilised by late morning but remains worrying given that he is still in intensive care".

"He is conscious, awake but tired," he said, adding that the singer would remain in the Gap hospital until Sunday at the earliest. He said the singer's age and the demands of his current tour had likely contributed to his malaise.

Jarreau's French trip was part of a tour scheduled to take him to Germany, Austria and Azerbaijan, and he was due to give concerts in the United States and Japan in the coming months, according to his website.

The Milwaukee-born singer's lengthy career has encompassed many musical styles. He has won Grammy Awards in the genres of jazz, pop and rhythm and blues and released more than 20 albums between 1975 and 2009.

Jarreau's affable ever-smiling personality and range of musical styles have made him popular with a wide audience all around the world.

As a teenager he started singing in Milwaukee bars.

After a degree in social sciences from the University of Iowa, he headed west, where he soon teamed up with the Brazilian guitarist Julio Martinez, and started playing in a club in Sausalito, near San Francisco.

Jarreau made his big breakthrough in Los Angeles in 1975, when he was invited to perform at the Hollywood Troubadour Club. His debut album, "We Got By", came in the same year; it was to prove an international hit.

In 1977 he went on a world tour and released his third disc, "Look to the Rainbow".

By 1981 Jarreau had become a household name, and his album "Breakin' Away" with its hit song "We're in this love together" made it into the US top 10, winning him two Grammys, for jazz and pop vocals.

His music had by then evolved towards pop, including the improvisational singing style known as scat.

The 1990s saw more hit albums: "Heaven and Earth" in 1992, which added R and B to the list of his Grammy awards, and then "Tenderness" in 1994.

The following YouTube video is a live Al Jarreau performance from 1993, and he is performing "Teach Me Tonight," with entertainer Lionel Ritchie playing the saxaphone.

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