Coffee lovers in the UK and Canada can now use their iPhone's Passbook app to pay for their Starbucks coffee. Previously, this function was only available to Starbucks' U.S. customers only.

Passbook is Apple's mobile wallet feature that runs on the company's latest operating system, iOS 6. The Passbook App allows users to store and organize tickets, boarding passes, store cards, and coupons. The coffee giant has been using similar technology for over a year now, which allows its customers to store money on a Starbucks Card that is loaded into a smartphone app available for both iPhone and Android phones.

Starbucks customers can now add their Starbucks Card to Passbook and scan their iPhone at the counter to complete the transaction.

The Starbucks app prompts its users to register their most-frequented Starbucks stores, which will enable the Passbook functionality in those specific Starbucks stores only.

"With Starbucks for iPhone, you can view your Starbucks Card balance, reload your card, view transaction history, and transfer balance between Cards. And there's more! Now you can track your Stars and see how close you are to your next free drink in the My Starbucks Rewards Experience," reports Geeky Gadgets.

The Starbucks app version 2.5 can be downloaded from iTunes Apps Stores free of cost. However, 9to5Mac reports that Starbucks app has not been updated for iPhone 5's taller screen.

The popularity of iPhones have been increasing rapidly. Owners of older iPhones and iPads have also started to get the latest update on their devices. Businesses like Lufthansa, Live Nation, Ticketmaster, American Airlines, et al have already got support for the Passbook app. Recent rumors also indicate that Apple is planning to use the Passbook app in its own Apple Stores also. With the increased use in iDevices, the use of Passbook is also expected to grow in the near future.

Now with the Starbucks app supporting Passbook, the morning cuppa from the nearest Starbucks stop each morning may get a little bit quicker.