Amazon is rewarding some of its most loyal Prime customers with a new perk.

Starting Tuesday, Prime member will get 5 percent back at Whole Foods when using their Amazon Prime Rewards Visa Signature credit cards. The card's 5 percent benefit was already available at Amazon.com.

The new benefit is the latest move from Amazon to create more connections to Whole Foods, the high-end grocer it purchased last year for $13.2 billion. Amazon earlier this month rolled out free, two-hour deliveries to Prime members from the grocery chain's locations in Austin, Cincinnati, Dallas and Virginia Beach. Plus, it's planning to make Prime the rewards program at Whole Foods stores.

These benefits should help Amazon strengthen Prime -- a central part of the company's business -- making it a must-have service for more customers. Plus, it'll help Whole Foods turn out more of Amazon's core base of shoppers.

While the Amazon Prime Rewards card is available only to Prime members, Amazon offers a similar card called the Amazon Rewards Visa that's more broadly available. On Tuesday, cardholders of the Amazon Rewards Visa will get 3 percent back at Whole Foods, just as they do at Amazon.com. Both of these cards offer 2 percent back at restaurants, gas stations and drugstores, and 1 percent on all other purchases.

You won't get this extra perk if you own the Amazon Prime Store Card or Amazon.com Store Card, which are both only available for shopping on Amazon.com and retailers that offer Pay with Amazon.