A source close to the couple told L&S, "[Katherine] picked the date — Dec. 23, just two days before Christmas. It just works because she'll be in the middle of a holiday break for her show, and she'll still have enough time after for a short honeymoon!"

Explaining Heigl's decision, the source said, "Everyone is already so full of cheer just before Christmas. So to throw in a wedding at that time — she just loved the idea!"

Just because Katherine is a big star now following her successful breakthrough movie role in Knocked Up doesn't mean she'll be having a paparazzi-friendly Los Angeles wedding. The snitch revealed, "Her idea is to get married under this snow covered tent her property with Josh in rural Utah. She wants glamour, so the dress is upscale. But she also wanted everything to feel down-to-earth, natural and beautiful."