Speaking to Collider, Waltz says:
I was talking about it again today but it might nor be a proper part, it might be one of these little what they call cameos… I was looking forward to meeting Miss Piggy. But they told me that dancing with Miss Piggy, for example, is almost impossible because she’s totally operated by puppeteers and dancing is, you have to dance with someone where there’s actually a real person inside so let’s see who I dance with.
But we can apparently take it for granted that he’s going to be dancing with someone.
Yep. Christoph Waltz, dancing. I’ll take that as a consolation for him not having a main role.
The new Muppets film starts filming in London in late January or February and should be released, in the US at least, by the end of 2013.
Waltz can currently be seen in Django Unchained, of course, and he’s also completed filming on Terry Gilliam’s Zero Theorem.