Nicholas Rodriguez, who plays a character "crucial" to the wedding scene, told People that an extravagant ceremony will be held in Connecticut.
He said: "We shot for two weeks. It's a ginormous scene with a huge budget, and everybody is pretty much in it... all of the girls and their spouses, Willie [Garson] and Mario [Cantone], and another big surprise cameo, Liza Minnelli."
It has been rumoured that the roles of Stanford Blatch and Anthony Marentino, who shared a kiss in the first instalment, are to be featured in the storyline.
Minnelli reportedly received $75,000 (£47,000) for her cameo appearance in the scene, during which she sings Beyoncé's 'Single Ladies (Put A Ring On It)'.
Of the Cabaret star's performance, Rodriguez added: "After the shoot, she said, 'I would like to have everyone's attention', and they pulled out a stool for her at the piano and gave her a mic and she sang a favourite of her mother Judy Garland."
However, Garson refused to answer questions about the supposed plotline, saying: "We're filming. I can tell you that. I don't want to get sued."
Stylist Patricia Field recently revealed details about an '80s flashback sequence in the sequel, which opens in cinemas on May 28, 2010.