Watch: Jessica Simpson Details "Happy Family" After Attending Ashlee Simpson Concert With Ex Eric JohnsonJessica Simpson's daughter Birdie Mae couldn't resist this opportunity. The "Irresistible" singer shared that when her 6-year-old's school hosted Spirit Week, Birdie jumped at the chance to channel mom for "dress as your favorite artist" day. Sharing a picture of the grade schooler, Jessica-who shares Birdie plus kids Maxwell Drew, 13, and Ace Knute, 12, with ex Eric Johnson-wrote on Instagram Oct. 9, "Bird wanted to dress up as meeeeee.