The news Friday comes after immense backlash mounted at the announcement Thursday that they would not require guests to wear face coverings when they reopen on July 15.
AMC CEO and president Adam Aron said the revised guidelines on masks were made in response hearing "an intense and immediate outcry from our customers."
"At AMC Theatres, we think it is absolutely crucial that we listen to our guests," Aron said. "Accordingly, and with the full support of our scientific advisors, we are reversing course and are changing our guest mask policy."
"As we reopen theatres, we now will require that all AMC guests nationwide wear masks as they enter and enjoy movies at our theatres. The speed with which AMC moved to revise our mask policies is a reflection of our commitment to the safety and health of our guests," he added.
Adams added that guests are encouraged to bring their own masks, but they will also be available at box offices for $1. If you are unwilling to wear a mask, you will not be admitted or allowed to stay at the movie theater.
In an interview with the entertainment outlet, Variety, Aron said that they "did not want to be drawn into a political controversy."
"We thought it might be counterproductive if we forced mask wearing on those people who believe strongly that it is not necessary," he told Variety.
Medical authorities including the U.S. Centers for Disease Control and Prevention have said that wearing face coverings play an important role in preventing the spread of COVID-19 in communities.
In the U.S., however, the medical guidance has oddly become embroiled in a culture war. Even President Donald Trump said at a recent news briefing he "didn't want to give the press the pleasure of seeing" him donning a mask during the health crisis.