The singer made the announcement just hours before he was set to take the stage.
Rod Stewart canceled his upcoming Australian concert due to a viral infection.
In a statement shared on Instagram just hours before he was set to take the stage, the "Maggie May" singer wrote, "Hello my friends. I'm absolutely downhearted that I'm disappointing my fans who bought tickets to A Day On The Green. Late this morning, I was advised that I have a viral infection and my throat is too irritated to sing."
His statement continued, "I'm only human and sometimes get sick just like you do. My greatest joy is performing for you, so I'm doing everything I can to get on the mend and back on stage!"
Stewart, 78, was meant to be joined by Cyndi Lauper and Jon Stevens at the show, which was going to be held at the Mt. Duneed Estate in Geelong.
His fans received the sad news well, sending the singer wishes of a speedy recovery.
The singer has yet to announce whether there will be a new concert date in replacement. He's set to perform five other shows in Australia, continuing on Tuesday, March 21, at Adelaide's AEC Arena.
As of now, the rest of the Australian performances are still on.
Besides his Australia and New Zealand tour, Stewart will continue his Las Vegas residency "The Hits" on May 3 at The Colosseum at Caesars Palace until May 15.