The actor revealed he has been diagnosed with stage four throat cancer during an appearance on The Late Show with David Letterman on Tuesday night (31Aug10), and he is currently undergoing painful and energy-sapping chemotherapy and radiation.
But he plans to follow late star Patrick Swayze's 2008 example and show the public what a cancer fighter looks like on the show, which will air live on multiple channels across America at the end of next week.
He'll join big names like George Clooney, Will Smith, Gwyneth Paltrow, Denzel Washington and Renee Zellweger when the telethon airs.
Queen Latifah, Stevie Wonder, Lady Antebellum and Green Day’s Billie Joe Armstrong are among those billed to perform during the television event.
The last Stand Up 2 Cancer in 2008 event helped raise more than $100 million (GBP66.6 million) for cancer research charities.