Bassey is recovering from stomach surgery, after being rushed from her Monaco home to hospital last month, suffering from abdominal pains.
Doctors have instructed her not to appear at the event which will include other music acts including Queen + Paul Rodgers, Annie Lennox, Simple Minds, Jerry Dammers, Amy Winehouse, Sugababes, Razorlight, Leona Lewis, Jamelia and Eminem.
Her spokesman Paul Carey said, “The Dame is hugely disappointed and was looking forward to the show immensely.
“Dame Shirley has been advised not to travel at the present time, so as to aid her continued full recovery following surgery last month.”
ABC1 screens the event at 10:10pm Saturday night.
Source: Digital Spy