McDonald’s (MCD) announced it is bringing back the popular barbeque pork sandwich McRib and customers can get it free with a funny little catch.

The fast-food chain will hand out free McRib sandwiches to the first 10,000 customers that shave off the beards they grew for "No-shave November."

All participants need to do is show off their freshly shaven face on their public Twitter or public Instagram profile, even with a face mask, using the hashtag #Shave4McRibSweepstakes and tag @mcdonalds.

The first 10,000 entries will receive a code for a free McRib sandwich to use via McDelivery with Uber Eats while supplies last. The codes are not available for Stories.

“Our bearded fans know… facial hair and the McRib just don't mix—believe me, I've tried,” David Tovar, McDonald's Vice President of U.S. Communications, said in a statement. “With the nationwide return of the McRib, we're helping fans enjoy every delectable moment by encouraging them to shave for a chance to win a free McRib.”

The McRib returns on Wednesday at participating restaurants via carry-out, drive-thru, the McDonald’s app and McDelivery.

McDonald’s has also teamed up with the No-Shave November nonprofit organization, which is dedicated to raising money for cancer research, prevention and education. McDonald’s will donate to the charity for every McRib purchase made Wednesday.

“No-Shave November is a month-long journey where we ask participants to put down their razors and 'get hairy' in the name of cancer awareness,” said Monica Hill, Senior Executive Director at No-Shave November. “We're thrilled McDonald's is supporting this important cause, getting both the bearded and the non-bearded involved beyond November simply by purchasing a McRib.”

On Monday, shares of McDonald’s were trading at $215.94 as of 2:18 p.m. ET, down $1.10, or 0.51%.

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A McDonald's fast food restaurant sign is seen in Beijing, Jan. 9, 2017. NICOLAS ASFOURI/AFP/Getty Images