The entertainers last performed together 23 years ago and were to reunite on stage Wednesday as part of an event celebrating the 25th anniversary of their PWL record label. However, the grounds at Hyde Park were deemed unsafe after recent bad weather and the show was canceled, the BBC said. It is unclear if it will be rescheduled.
Minogue and Donovan are both former cast members of TV's "Neighbors" in Australia. Their duet "Especially for You" was an international hit in 1988.
"I am so sorry to hear that the concert tomorrow had to be canceled," Minogue said on her Web site Tuesday. "I feel for all the fans who had bought tickets to this special event. Jason and I were rehearsed and excited to share this moment with everyone."
Also booked to perform at the concert were Steps, Sinitta, Sonia, Rick Astley, Bananarama, Pepsi and Shirlie and Brother Beyond, the BBC said.