The highly anticipated Samsung Galaxy S2 Android Ice Cream Sandwich update has reached the U.K, with the O2 operating service announcing the rollout on their Twitter account.

Samsung kept to its promise and started rolling out the Android 4.0 update in Europe before the end of March.The UK is the latest to receive the upgrade on O2, but S2 owners on other networks including, Vodafone, T-Mobile and Orange, will have to wait for the operators to finish testing the update on their devices, according to Tech Radar.

There is no official word on when the upgrade will reach the U.S, but Android enthusiasts could have to wait a little longer after Samsung revealed that the updates would have staggered release dates across the world. In a recent announcement, the U.S. carrier Verizon said the upgrade would be coming to Samsung devices in the near future, but no date was specified.

ICS for Galaxy S2 will be available today in Europe, including Poland, Hungary, Sweden and Korea & gradually roll out to other markets, the company said in a press statement.

Other devices that will receive the upgrade include the Galaxy Note, Galaxy S2 LTE, Galaxy R, Galaxy Tab 7.0 Plus 7.7, 8.9 and 10.1

The company has also announced the status of Android 2.3 Gingerbread updates. Samsung Electronics has completed upgrading the Galaxy devices to Gingerbread last year by providing software upgrades to both Froyo and Gingerbread, said Samsung. With the ICS upgrade, Samsung Electronics has solidified its position as the leader of Android devices.

A firmware update for Gingerbread devices will also roll out at the end of the month on devices including the Galaxy S, Galaxy Tab 7, Galaxy S Plus, Galaxy S SCL (Super Clear LCD), and Galaxy W.

The Galaxy S2 and Galaxy Nexus were heralded as two of the most popular smartphones of 2011, with several features packed into a slim, sleek case. The Ice Cream Sandwich upgrade will bring refinements and a touchscreen that allows users to unlock the phone with their face, according to the BBC.

ICS for HTC Vivid on AT&T's Network

Meanwhile, AT&T became the first U.S carrier to bring the Android 4.0 updates to one of its devices on Friday. The operator has started rolling out the update on the HTC Vivid. 

After installing the software update, customers can now enjoy the optimized audio experience of Beats by Dr. Dre Audio and new and improved HTC Sense experience, AT&T said in a statement.

AT&T also revealed other devices that would be getting the update in the future. These included:

LG Nitro, Motorola ATRIX 2, Motorola ATRIX 4G, Pantech Burst, Pantech Element, Samsung Captivate Glide, Samsung Galaxy Note, Samsung Galaxy S2, Samsung Galaxy S2 Skyrocket and Samsung Galaxy Tab 8.9.