ET‘s STEVEN COJOCARU spoke to Katherine Heigl over the weekend during promotion for her new film, 27 Dresses, in an interview to air on Monday, December 17th.

Heigl shared details of her upcoming wedding to musician Josh Kelley, “You have a fantasy of this big day, this big moment and the sentimental aspect of it, but I think at the end of the day I find that there is a different level for both of us to the relationship. It is important to honor our families and honor the tradition, to stand up in front of all of these people and say, ‘It’s you and me and that’s it for life.’ I hope I can just chill out, somebody might need to slap me!”

Describing her wedding dress Heigl says, “It’s A-line with a big floofy skirt and strapless. I get slightly distracted by the variety and how many different directions you can go, but I keep coming back to what I feel most comfortable in.” As for the guest list she adds, “No celebrities are coming, it is all just friends and family.” The bride-to-be gave us a hint about her honeymoon getaway, “We’re going to a beach, somewhere beautiful and romantic.”

About the pressures of being an “It Girl,” Heigl says, “‘It Girl’ freaks me out because that means right now, so what about tomorrow? I’m trying to have more of a lasting career.” She jokes about her life being a fairy tale, “I have to knock on wood because any minute now the wicked witch will come in and ruin it all with a poisoned apple.”

ET