The leak comes via well-regarded Vietnamese site Tinhte, revealing footage of the mysterious device. You can check out the clip below, which yields what could be the S3's hardware specifications.
An 8-megapixel camera is tipped to squat around the back of the phone, while a 1.4GHz quad-core processor is reckoned to be humming under the bonnet. 16GB of storage plus a microSD card slot are also mentioned, while the S3 is also pegged to sport NFC tech and a 2,050mAh battery.
That display looks to have a resolution of 720x1,184 pixels, landing it with a dpi of 320, just shy of the 326dpi offered by the 3.5-inch iPhone 4S, but mighty impressive on a screen that big. The phone pictured has the model number GT-i9300, which is reckoned to be the model number for the Galaxy S3.
Ice Cream Sandwich is also on board -- as well as the notable on-screen buttons that the phone's 'about' page is proudly boasting Android version 4.0.3.
As for the design, I wouldn't be surprised if this isn't the final look for Samsung's newest toy. Recent reports suggest that crafty ol' Samsung is packing S3 samples in generic casing to send out to partners, in order to keep the true design a secret until the 3 May reveal.
This information chimes with what we're expecting from the Galaxy S3 -- a modest upgrade to the Galaxy S2 that makes each individual lump of hardware a little bit more potent. That may not sound very exciting, but it could add up to a seriously desirable smart phone.
Stay tuned for more info -- in the meantime let me know your thoughts in the comments, or on our Facebook wall.