Osbourne, who turns 65 Tuesday, urged his fans to celebrate his special day by helping those in need via Twitter.
The Godfather of Heavy Metal isn't the only celebrity to use his birthday to raise money for a good cause. Former Spice Girls star Mel C, The Wanted stars Nathan Sykes and Max George and Sir Paul McCartney have also urged fans to donate to The Royal Marsden on their especial days.
The Royal Marsden has raised £100 million to fund pioneering developments in cancer care over the last 10 years, according to its website.
2014: The Year in Music [PHOTOS]