Richie, 29, who designs her own collection Winter Kate, is set to give her fashion advice as a mentor on the new NBC reality series along with Simpson, 30, and menswear designer John Varvatos.
The show is set to be hosted by Aussie model Elle Macpherson.
In a statement to Us Weekly, the show's executive producer Ben Silverman said: 'Jessica, Nicole, John and Elle make the most exciting team we have ever worked with on a reality television show and we are thrilled to feature such an extraordinary group of mentors and designers.'