My take on this is slightly different from Eggy's in that I wanted to get a somewhat better skin tone (ie, reduce the orange color cast in the original).
Since the original was so blurry and noisy, and this was only an example, I didn't spend a lot of time on the cutout / selection process, so halos are visible against the darker background when the composite is put together. With more care, these could be reduced.
Attachment #1 is a screen grab with the checkerboard pattern that shows the background has been removed
#2 is the actual PNG (note - it shows up in this preview with a white background, even though it is transparent).
#3 is my guess at the sort of background you might be thinking about.
HTH,
Tom M