There has been some images of Mami in this outfit in the past few days.
Does anyone know where this is from?
I don't want to miss any Madoka Magica news ;-)

It comes from the PSP game, apparently it is from a bonus path.

From what the Wiki says, Mami becomes a magical girl idol in the bonus route. (spoilered just in case)

In that outfit, Mami reminds me of Kise Yayoi and a bit of Madoka.