What's the bet that Constantine 'romances' Miss Piggy to fool her and the rest of the troupe (excluding Fozzie, Gonzo and perhaps Rowlf) and ends up proposing to make things even more complicated? That would explain the wedding scene and why Constantine was seen in London.
I see I'm not the only one who thinks this. Here is my prediction, and I'll go out on a limb, right or wrong: Constantine romances Miss Piggy--partly because that's what any
normal cold-blooded amphibian would do, but also to continue the masquerade that he's Kermit. And, in order to stop the wedding, I'll betcha Kermit has to actually declare his feelings for Piggy. Even then, I think Piggy might torment him by actually contemplating marriage with someone who
wants to be married to her. You know what they say--"a frog in the chapel is worth two frogs who aren't." If I get my wish, this will lead Kermit to say, "Oh yeah? Well, show's what
you know!" and take Constantine's place in the wedding. (I would REALLY like to see this, even though I know they are already married.)
The other alternative is that, after convincing her that she cannot marry Constantine because he isn't the frog she really loves, that Kermit ONCE AGAIN weenies out of commitment. In typical Kermit fashion, he is usually able to scuttle Piggy's plans to find happiness without him and get her to declare her feelings for him without a lot of commitment in return. Here's hoping Piggy gets something more than a used wedding dress in return.