If you checked Facebook or Twitter Tuesday morning, you might have seen some of your friends suddenly turning their profile pictures purple.

The movement is for World Cancer Day, and Chevrolet has launched a website that lets you "Purple Your Profile" for a good cause.

The automaker said it will donate $1 to the American Cancer Society for every purple profile, up to $1 million.

Action is the strongest way to improve the lives of those with cancer today and help find cures to end the disease tomorrow. Help us finish the fight and purple your profile now.

— Chevrolet, Purple Your Profile

Chevy also encouraged people to get involved by giving a cancer patient a ride to and from treatment, via the American Cancer Society's Road to Recovery program.

"Every day thousands of cancer patients need a ride to treatment, but some may not have a way to get there," the ACS says.

If you're interested in volunteering a ride for a cancer patient, you can search for a Road to Recovery program by ZIP code.