Stevie Wonder is to undergo a kidney transplant later this year.
The 69-year-old star made the announcement during his performance at British Summer Time Hyde Park.
He confirmed he'd already found a donor and would perform three more shows before going under the knife in September.
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Stevie said he was making the announcement in order to end "rumours" about his health.
He continued: "I'm all good, I'm all good, all good, I have a donor and it's all good.
"I want you to know, I came here to give you my love and thank you for your love. I love you and God bless you."
I'm all good, I'm all good, all good, I have a donor and it's all good.
Stevie previously insisted he's always had a positive outlook on life, regardless of the challenges he's faced.
The music icon told The Guardian in 2002: "I'm always optimistic, but the world isn't.
"People need to make a jump to a place of positivity but they put it all on one person to make it happen.
"It takes everybody. And the mindset has to be different."
The I Just Called to Say I Love You hitmaker - who has been blind since shortly after his birth - also insisted he's never seen his disability or his race as a barrier to success.
He said: "Do you know, it's funny, but I never thought of being blind as a disadvantage, and I never thought of being black as a disadvantage.
"I am what I am. I love me! And I don't mean that egotistically - I love that God has allowed me to take whatever it was that I had and to make something out of it."
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