While Windows Phone fans in the U.S. are eagerly awaiting the launch of the Microsoft Lumia 640, they will be pleasantly surprised to learn that carrier AT&T will also be releasing the smartphone's bigger sibling - Lumia 640 XL - this month.

AT&T and T-Mobile are already set to make available their variants of the Microsoft Lumia 640, but it is the former which has upped the ante by grabbing the hotly-anticipated Lumia 640 XL to its kitty.

The news comes courtesy of a Microsoft representative, who revealed to WinSuperSite at an even that AT&T will be offering both the Lumia 640 and Lumia 640 XL from June.

Reportedly, the AT&T Lumia 640 will go one sale soon "possibly within next week" as well, conceivably giving company to the T-Mobile variant which will hit the shelves on June 17. However, the bigger sibling Lumia 640 XL will hit the retail shelves by June end.

When it comes to pricing, the Lumia 640 is expected to be a low- to mid-range smartphone, costing between $100 and $150, whereas the Lumia 640 XL will allegedly cost $100 more than the smaller sibling.

The pricing of the Lumia 640 and the Lumia 640 XL mentioned is for the unlocked variant. The on-contract versions will of course be cheaper and the pricing of the new Microsoft Windows Phones could vary depending on the carrier. Cricket currently offers the unlocked Lumia 640 for $129.99.

For the unfamiliar, the Lumia 640 XL touts a massive 5.7-inch IPS LCD screen with a 720p resolution, while the Lumia 640 has a 5-inch 720p screen. Both devices have Corning Gorilla Glass 3.

The Lumia 640XL phablet will also pack in a powerful 13MP rear-facing camera with Carl Zeiss optics and 1080p full HD recording capability. Selfie lovers will need to contend with a 5MP secondary camera.

The smaller sibling packs in an 8MP and 1MP primary and secondary cameras, respectively.

Under the hood, both the Lumia 640 XL and Lumia 640 will pack in a quad-core Qualcomm Snapdragon 400 processor, clocked at 1.2GHz and 1GB of RAM. The smartphones will come with 8GB of on-board memory. The Lumia 640 XL boasts a powerful 3,000mAh battery which better the 2,500mAh one on the Lumia 640.

Both the Lumia 640 and Lumia 640 XL will come with the latest Windows Phone 8.1 Update 2 OS out of the box.

AT&T's website lists the Lumia 640 XL as "coming soon" but there is no mention of the Lumia 640.