Walmart is launching a service that will have a worker delivering fresh groceries and putting them in your refrigerator when you're not home.

The nation's largest grocer said Friday that it will offer the service this fall for more than one million customers in three cities: Pittsburgh, Kansas City, Missouri, and Vero Beach, Florida. Later this year, the service, called InHome Delivery, will also accept returns for items purchased on Walmart.com.

The new service is part of Walmart's drive to expand its shopping options that include curbside pickup and online grocery delivery.

Amazon offers a similar service in certain cities, dropping off packages inside homes, garages or car trunks. But the service is not for groceries.

With Walmart's new service, customers place a grocery delivery order online and then select InHome Delivery and a delivery day at checkout.

Walmart workers will use smart entry technology and a proprietary wearable camera to access the customer's home. That allows shoppers to control access into their home and give them the ability to watch the delivery remotely.

Walmart said that the workers will go through an extensive training program that would prepare them for things like how to select the freshest groceries and how best to organize the refrigerator. Walmart said it will share the fee details ahead of the fall launch.