Darius Rucker is lending the American Cancer Society a hand - well, actually, a voice - to promote their new 'More Birthdays' campaign. Operating under the motto "a world with less cancer is a world with more birthdays," the initiative's goal is to help cancer survivors celebrate a lot more birthdays by promoting healthy living.

For the project, Rucker made a video of himself singing an a cappella rendition of 'Happy Birthday.' "I hope that the people who hear my 'Happy Birthday' song remember life is precious," Rucker tells the Boot, "I wanted to get involved because cancer affects everybody. Cancer is such a devastating thing." He should know; the country star's father-in-law and niece have cancer right now and he admits, "It's been pretty tough."

Rucker says the American Cancer Society wants to do "more than just awareness; they want to help people stay healthy. Birthdays are even more of a reason to celebrate life."

Also taking part by creating their own special versions of 'Happy Birthday' are Keith Urban, Lady Antebellum, and Big and Rich's Big Kenny.

Head to the American Cancer Society's official website for more information.