Kylie has pulled out of a performance with U2 due to exhaustion, having resumed her world tour.
The star, who is still not fully fit after undergoing chemotherapy for breast cancer, was due to repay a favour and sing with U2 after Bono joined her on stage for a duet on the first night of her Showgirl Homecoming tour.
Friends were worried that Kylie, who underwent an intensive fitness regime to build up stamina for her 2 1/2 hour show, was doing too much. Bono apparently told Kylie to rest and relax and not to worry. What a gent! | 
