The British singer spent the day Wednesday at Cedars-Sinai Medical Center where he underwent extensive tests, it said, announcing the cancelation of his "Million Dollar Piano" shows on Thursday, Saturday and Sunday this week.

"Elton developed a serious respiratory infection last weekend while performing at The Colosseum (in Vegas) on Sunday, May 20," said a statement emailed to AFP by his publicist, Fran Curtis.

"This week the condition worsened, even with medication and rest, resulting in Elton being hospitalized at Cedars-Sinai Medical Center... at 6:00 am Wednesday, May 23, where he remained throughout the day for extensive tests.

"Those tests resulted in the attending... physician recommending that Elton not perform any concerts for approximately seven days with complete rest and antibiotic treatment to cure his respiratory infection and prevent any damage."

The flamboyant 65-year-old star began a three-year residency with the "Million Dollar Piano" show in Vegas -- at the Colosseum, part of the Caesar's Palace casino-hotel complex, last September.

In the statement, John said he was "very disappointed" at having to cancel.

"It feels strange not to be able to perform these 'Million Dollar Piano' concerts at The Colosseum," he said.

"I love performing this show and I will be thrilled when we return to The Colosseum in October to complete the 11 concerts soon to be scheduled. All I can say to the fans is sorry I can't be with you."

John is due to perform in a concert in front of Buckingham Palace on June 4 -- along with Paul McCartney, Kylie Minogue and Chinese piano virtuoso Lang Lang -- to celebrate Queen Elizabeth's diamond jubilee.

John, one of music's biggest global stars since his early career with songs like "Rocket Man" and "Candle in the Wind," is known for his marathon power-packed concerts and relentless touring.

He is due to tour in Europe in June and July, before returning to the United States and Canada in September, according to his website concert schedule.

His respiratory illness are the latest in perennial health woes suffered by the "I'm Still Standing" star over the years, including drug abuse, depression, bulimia and heart problems, according to ABC News.