Studios have embarked on many unlikely side ventures and offbeat promos in recent years.But Columbia Pictures might be the first to delve into the wedding business to drum up interest in a film. With the help of Col’s marketing team, Pennsylvania natives Michelle Golightly and Shaun Bollinger will tie the knot at the premiere of romantic comedy “Made of Honor” in New York on April 28. Officiating is “Entertainment Tonight’s” Mary Hart, who became an ordained minister so the marriage would be legally binding. “I actually do want this to be a classy affair,” says Sony marketing prexy Valerie Van Galder. “I don’t want it to be an icky publicity stunt.” Lisa Zaks, who works in Sony’s New York publicity office, hatched the idea for the pink-carpet wedding, which will be webcast live on Crackle.com and covered on “ET.” So, how far will Columbia go in blurring the lines between real life and celluloid life? “Patrick (Dempsey) and Michelle (Monaghan) will be there for the event, but, you know, the couple has their own bridesmaids and friends,” Van Galder quips.