About 65 percent of the company's stores and clubs are located in regions that already have government mandated face coverings, according to a company blog post . The new rule starts Monday, July 20, at all locations in the United States.

"To help bring consistency across stores and clubs, we will require all shoppers to wear a face covering starting Monday, July 20," Walmart US chief operating officer Dacona Smith and Sam's Club chief operating officer Lance De La Rosa said in the blog post. "This will give us time to inform customers and members of the changes, post signage, and train associates on the new protocols."

Signs will be posted throughout Walmart stores and the company has employed "Health Ambassadors" who will remind guests of mask requirements at store entrances. Ambassadors will wear black polo shirts and help customers who don't have a mask find a solution. The company says they are currently considering several options for customers who show up sans mask.

Associates at Sam's Club will also inform members of the new policy at the entrance. However, they'll offer complimentary masks to members who don't have one.

Walmart isn't the only retailer to enforce the new rule during the novel coronavirus pandemic. Last week, Starbucks said it will require customers to wear facial coverings or masks in all U.S. locations, reported CNN . Best Buy and Costco have similar requirements.