The legendary composer was expected to conduct The London Symphony Orchestra at the Royal Albert Hall this Friday, October 26, in a celebration of his remarkable career.
Instead, the 86-year-old has been admitted to hospital.
Concerts with the Vienna Philharmonic Orchestra on November 3 and 4 have also been affected.
All three shows will go ahead with a replacement conductor and Williams expressed his sadness in a message to his worried fans.
The Royal Albert Hall issued an pofficial statement on the composer’s behalf: “John is so sorry that an illness prevents him from conducting Friday’s concert, and he’s grateful to his friend Maestro Dirk Brass for taking the podium in his place.
“He so wishes he could be with everyone, and the knowledge that 5,000 of his friends will be joining together to celebrate his music is a great comfort to him as he recovers. He wishes everyone a very joyous evening of music.”
There has been no further information about why Williams was admitted to hospital or how serious his condition is.
Just last week news leaked that he was composing new music specifically for the upcoming Star Was 9 trailer.
The leak said: “The big rumour is that there will be a teaser attached to the Super Bowl and the main trailer will come our way at the Star Wars Celebration in April in Chicago.
“John Williams will compose a track mixed with music from the prequel and the original trilogies. It will be their way of letting fans subliminally know that prequel content is coming. This special track won’t be in the movie but dedicated to the trailer only.”
This is huge news because fans know that Star Wars 9 will be Williams’ last journey to a galaxy far, far away. He already announced his retirement from the Star Wars franchise but film fans will be hoping he is still able to complete one last magnificent composition.
The first Star wars trailer is expected to drop next February, and simply would not be the same without that classic Williams sound.