Sir Elton John has cancelled a headline performance at London's Hyde Park after being diagnosed with appendicitis.
The performer had been due to perform at the concert on Friday night, topping a bill which also features Elvis Costello and Ray Davies.
He called in doctors after being taken ill during his European tour.
Sir Elton John will join forces with his celebrity friends in a fight against Aids this Valentine's Day.
Sir Elton John has caused controversy in China by dedicating his own concert in Beijing to political critic Ai Weiwei.
The announcement, minutes into his performance, is said to have sent a murmur of shock throughout the audience as Ai remains a touchy subject for the Chinese government.
The two men met before the gig and Ai tweeted: “I super like him.”
Audience members reported that Sir Elton told the crowd that the concert was dedicated "to the spirit and talent of Ai Weiwei".
The sculptor and installation artist, who has used his art to draw attention to social injustice, was detained for nearly three months last year and he remains barred from leaving China.
Sir Elton John and his partner David Furnish are to have a second baby, according to The Sun.
It is thought that the Rocket Man star, 65, and Mr Furnish, 50, will use the same surrogate who bore son Zachary, 22 months, for the couple.
A source told the paper: "Elton and David love this lady like a sister and they feel indebted to her for life. Naturally she has been well rewarded, but her identity will never be revealed."
In an exclusive interview with ITV1's Daybreak the singer also revealed he and partner David Furnish would love another child.
A concert by Sir Elton John at a new venue in Blackpool was cut short tonight by strong winds.
Nearly two hours into his set, Elton told a disappointed crowd of almost 11,000 that on police advice he had been told to stop playing.
"I have been told there is some really bad weather on the way. The police say you need to leave right now in an orderly fashion. I'm sorry but I don't want anyone to be hurt. I'll make it up to you."