According to the US book-selling giant, the OTA software boost is currently available in both the UK and the US and will bring the eligible Nook duo up to version 2.1.0.
In addition to access to the Play store, the update will also see Google rollout YouTube, Gmail and Chrome apps to the Nook devices.
The introduction of Google Play will see software availability on the Nook soar from 10,000 to 750,000 apps - potentially turning the Barnes & Noble tablets into legitimate iPad and Kindle killers overnight.
Both the Nook HD (pictured, top) and Nook HD+ had previously been criticised for lacking a wide app selection like their rivals.
"This deal is about plugging that gap. Consumers told us they wanted more apps," said Barnes & Noble CEO William Lynch.
"By adding Google Play to Nook HD and Nook HD+, we are offering our customers even more great entertainment on our award-winning tablets," he added.
Lynch continued: "Now with access to more than 700,000 apps and the best reading experience available, both are must-see products for entertainment lovers looking for high-quality tablets at incredibly low prices."
However, independent analysts were less convinced, dubbing the move a significant improvement but not a "game-changer."
"It's a positive product enhancement - adding the Android features is a great step. It makes this device competitive," said Sarah Rotman Epps of Forrester Research.
The 7in Nook HD retails for £159, while big brother the 9in Nook HD+ sells for £229.