Olivia Wilde took preparing for her role as a stripper in “Butter” seriously. “We went down to Action Central Cabaret in Shreveport, Louisiana, and I got to hang out in the locker room with the strippers, and they were so sweet,” she told us at the Cinema Society screening of the film at AMC Lincoln Square Thursday night. “They were really helpful. But also being able to hang out with the strippers let me know a little about the logistics of working at a strip club. I learned that what they do is incredibly difficult . . . It’s really an underappreciated dance form.” Wilde also read Diablo Cody’s book “Candy Girl” about her year as a stripper. “That was the most useful thing,” she said. Wilde was joined by Harvey Weinstein and co-stars Jennifer Garner and Alicia Silverstone at the DKNY and Forevermark after-party at the Double Seven. Silverstone, a strict vegan, avoided dairy products while on set. “I don’t want to touch butter,” she said. “The good news is, in the movie they use wax.”