Bentonville, Arkansas (CNN Business) Walmart is betting it can convince time-strapped customers to let strangers deliver groceries into their refrigerators while they're away from home.

In a new service announced Friday, customers will be able to order groceries online, and then a Walmart worker will drive the food from a nearby store and deliver it to fridges in customers' kitchens or garages. It is Walmart's latest innovation in its grocery business , which makes up more than half of the company's annual sales.

Walmart employees will deliver grocieries straight to customers' fridges.

Walmart piloted its new service in New Jersey for five months and is ready to expand. The option will be available to more than a million customers this fall in Kansas City, Pittsburgh and Vero Beach, Florida. Walmart charges a fee for regular grocery delivery orders, and it did not disclose how much customers will have to pay for in-home delivery.

Here's how the service works: Customers can purchase groceries online and select a delivery day. Walmart's employees will wear a camera when they enter customers' homes, allowing shoppers to watch the process live from their phones. Customers won't have to pay for a camera, but they will have to purchase a special door lock. Walmart did not say how much the lock will cost.

Walmart believes it can entice shoppers with another convenient perk as part of its in-home delivery service: Later this year, customers will be able to leave their returns from Walmart's website on their counter and the employee will bring the item back to the store.