Rumours are that the song is called 'Grown Woman' and was produced by Timbaland.
In the snippet below you'll hear a weird voice that isn't Beyoncé's and then some acappella bits of what sound like the song's chorus.
In it she sings, "I'm a grown woman, I do whatever I want", which is certainly factually accurate.
Anyway, here it is.[youtube]QLfL76GY85w[/youtube]
This is all getting a bit exhausting now isn't it.