Ozzy Osbourne may be known as the "Prince of Darkness," but he showed a lighter side recently by visiting patients at Birmingham's Children's Hospital.

The Black Sabbath vocalist has a past with the hospital, explaining to The Mirror, "My son Louis was in Birmingham Children’s Hospital for quite a while as a child and the staff took such good care of him, something which I will always remember."

Osbourne lent his support to the Sunday Mirror's campaign to raise £3.65 million for the hospital's Star Appeal, which will help build a pioneering Rare Disease Center. The Star Appeal's center will provide a single location within the hospital for assessments, diagnosis, treatment, information, research and peer-to-peer support.

“They do amazing work for kids and I’m really pleased to drop in and once again show my support for the Star Appeal – it’ll be a national center that will help families not only in my hometown, but also across the country,” said Osbourne.

During his visit, Ozzy met with a two-year-old boy who is suffering from a rare strand of neuroblastoma who underwent intricate surgeries to remove tumors from his stomach. He also met a 15-year-old boy who suffered kidney failure last year, but recently had a transplant.

To learn more about the Star Appeal's plan, click here.

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