ET spoke to Simpson last month in New York City as she was honored at the 40th Annual Outstanding Mother Awards, where she opened up about the most rewarding part of motherhood. The fashion mogul often shares sweet family pics of Ace as well as her eldest child, 6-year-old daughter Maxwell, with husband Eric Johnson.
"The fact that people think I'm doing a pretty good job [as a mother] is the best compliment," Simpson said. "The most rewarding part of being a mother is really just watching my kids grow. It's like, how much knowledge they have about life is just so meaningful to me, and how much heart they put into everything they do. There's just nothing like the innocence of a child."