Mirrors will soon double as billboards at O'Hare International Airport, the Chicago Tribune reports.
Together with a company called Mirrus, Clear Channel Outdoor plans to install 40-inch mirrors in some airport restrooms that will display ads -- when they're not displaying your reflection.
If someone goes to the sink, the ad automatically will move aside.
Clear Channel and Mirrus plan to hang the mirrors during the next three months at several U.S. airports, according to the Tribune.
Video and still ads periodically will change and show different products depending on whether they appear in men's or women's bathrooms. Advertisers can count how many people see a mirror ad and how long each person looks at it.