Jessica Simpson and fiance Eric Johnson are making two of their first big decisions together as a couple: when to get married and where to spend Christmas.

"We have not started any planning," Simpson, 30, told Us Magazine at NBC's live special 'Christmas in Rockefeller Center' in New York City Tuesday. "I'm trying to get through all this promotion," said the singer about her new album, 'Happy Christmas.'

"Who knows what will happen?" Simpson told Us. "I personally have no idea! I have not set a date and I can't even think about putting together table settings at the moment. I'm just gonna enjoy the engagement and we'll get married the moment we feel like it."

Her future husband, former NFL player Johnson, 31, (who was on hand for the tree lighting) proposed to her on Nov. 11 at her Los Angeles home after dating for about six months. He popped the question with a Neal Lane ring worth an estimated $150,000, featuring a 5-carat ruby (her birthstone) and 3-carat diamonds.