Marriott hotels will require guests to wear masks in lobbies and other public spaces starting July 27.

The Bethesda, Maryland-based hotel giant — which has more than 7,300 hotels worldwide — has been requiring employees to wear masks for several months. But in a video message released Monday, CEO Arne Sorenson said the mandate is being extended to guests.

“Health experts have made it clear that wearing face coverings in public spaces is one of the easiest steps that we can all take to protect one another and reduce the spread of COVID-19,” Sorenson said in the video, after removing his own cloth mask.

Marriott’s announcement follows guidelines for travelers issued last week by the American Hotel and Lodging Association, a trade group. Those guidelines call on guests to wear masks and practice social distancing in hotel common areas. They also ask guests to go without housekeeping during their stays and use contact-less check-in and checkout when possible.

The association also applauded states that require masks in indoor public spaces.

Marriott is the largest hotel chain to issue a mask requirement. Hyatt Hotels already require guests to wear masks in public areas in U.S. and Canadian hotels. Hilton said Monday it plans to require guests to wear masks, but it hasn’t released a start date.