Elton won't be going to his own charity bash on November 10 because he's filling in for George Michael at Perth Arena on that date.
So Kevin Spacey will take the rocker's place and co-host Saturday's EJAF Winter Ball.
Michael, who nearly died last year of pneumonia, cancelled his Symphonica tour due to major anxiety, saying doctors told him he needed complete rest and post-traumatic counselling.
Around 600 guests are expected for the Elton John AIDS Foundation gala at Battersea Power Station, featuring performances by Emeli Sande and Labrinth.
