About a decade following her split from Lachey, Simpson confessed to CNBC's Closing Bell on Thursday she had made a poor financial decision by choosing to wed Lachey.
"The biggest money mistakes? I don't know. For some reason I thought of my first marriage," Simpson, who is currently married to Eric Johnson with two children, said with a laugh when questioned about personal or business mistakes of her past that helped her grow as a person.
"That's actually a common answer believe it or not," host Kelly Evans replied.
But the monetary cost of her divorce clearly hasn't impacted Simpson's lifestyle very much. Simpson, who has an extremely successful fashion line, said she's ready to make her next billion dollars in the next five to ten years. She also plans to record music again and go on tour.
Lachey has said in interviews his split from Simpson was best for both of them and they never really stayed in contact or remained friends -- although there was no animosity between them either.
Simpson, 35, and Lachey, 41, starred in the MTV reality show Newlyweds: Nick and Jessica from 2003 to 2005. Simpson later starred on The Price of Beauty but it only lasted one season in Spring 2010. More recently, she served as a mentor on two seasons of Fashion Star in 2012 and 2013.
Since the Newlyweds series, Lachey hosted The Sing-Off and also competed on Dancing with the Stars and an NBC celebrity reality competition called Stars Earn Stripes.
Simpson's kids with Johnson are Maxwell Drew, 3, and Ace Knute, 2. Meanwhile, Lachey also has two children -- son Camden John, 2, and daughter Brooklyn Elisabeth, 8 months -- with his wife Vanessa Lachey.