The couple revealed the gender to People on Thursday, and Ashlee voiced her excitement over discovering the sex of their upcoming addition.
"I like to know," she said. "I want to do the nursery."
The 30-year-old younger sister of Jessica Simpson got engaged to Evan, 26, in January after dating for nearly six months. The couple tied the knot in August during an intimate ceremony in Connecticut.
Ashlee first announced she was pregnant in December. This will be the couple's first child together, though Ashlee is already mother to 6-year-old son Bronx Mowgli, from her previous marriage to Fall Out Boy's Pete Wentz.
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