Story highlights Elton John is released from Cedars-Sinai Medical Center after testing and treatment

John, 65, became ill while performing at Caesars Palace in Las Vegas last weekend

Doctors order seven days of complete rest and antibiotic treatment

His next three shows at the Caesars Colosseum are canceled

Elton John checked into a Los Angeles hospital Wednesday, where doctors diagnosed the 65-year-old singer with a serious respiratory infection, his publicist said Thursday.

John was released from Cedars-Sinai Medical Center in Los Angeles after testing and treatment Wednesday, according to his publicist.

John became ill while performing his "Million Dollar Piano" show at The Colosseum at Caesars Palace in Las Vegas last weekend, leading him to undergo testing at Cedars-Sinai on Wednesday.

"Those tests resulted in the attending Cedars-Sinai 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," a statement from the publicist said.

His shows Thursday, Saturday and Sunday at The Colosseum have been canceled, the statement said.

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