Xiao Ke, the popular singer-songwriter, also expressed his shock and said that Houston's style was unforgettable.

"Take a look at what she did and you'll see she was a born singer," said the Beijing-based musician, who has written hits for stars including Faye Wong and Na Ying. "Whitney Houston conquered the world with her voice."

Houston had been in LA for Sunday's Grammy Awards and was staying at the Beverly Hilton, where she was also scheduled to perform at a pre-ceremony party hosted by Clive Davis, founder of Arista Records.

Lieutenant Mark Rosen of the Los Angeles County Police Department told the Associated Press that emergency services were called to the singer's room on the fourth floor. Paramedics, who found her in the bath, were unable to resuscitate her and she was pronounced dead at 3:55 pm.

The cause of death is still under investigation, he said, adding that there was "no obvious signs of any criminal intent".

Whitney Houston, who died on Sunday aged 48, performs in this file photo taken at the 37th Annual American Music Awards in Los Angeles in November 2009. [Matt Saylers/AP]