The singer bonded with the former Victoria's Secrets model during the season finale of fashion reality show Project Runway.
Simpson, 30, and Klum, 37, hit it off when they both fell in love with a floor-length polka dot dress designed by one of the contestants,
'We should go to a party together. We'd both wear it,' an excitable Klum declared.
Simpson, who has her own range of clothes and shoes, was invited to be the guest judge on the Project Runway final.
Aspiring fashion designers Mondo Guerra, Gretchen Jones, and Andy South are all fighting it out. On offer are the champion's crown, $100,000 from L’Oreal Paris, a fashion spread in Marie Claire magazine, and a $50,000 technology suite by HP and Intel. There is also the opportunity to design and sell an exclusive collection on Piperlime.com.