Mark Ruffalo, Samuel L. Jackson, Harry Potter's James Phelps and other male stars are concerned about breast cancer—not just for the women in their lives, but because it affects men as well. (Some 2,350 men will be diagnosed with breast cancer this year—and 440 will die from it.)

To get the word out, they're joining the cleverly named hashtag campaign, #InTheNipOfTime, created by OneForTheBoys as a way to educate men about breast cancer—including how to spot the signs and seek help.

Jackson narrates the campaign's animated PSA, which honestly makes you sit up and listen. (Do you want to be the one to ignore Samuel L. Jackson?)

Take a peek at #InTheNipOfTime supporters flashing some nip below.

For more information, visit the official website for OneForTheBoys, or tweet them support using the #InTheNipOfTime hashtag.