Jessica Simpson sizzled in an Etro dress on the red carpet at Us Weekly's Hot Hollywood bash at L.A. hotspot Eden on Tuesday.

But our Style Icon of the year was honest about one well-known fashion "don't." "The mom jeans...they kinda didn't work for me!" the engaged superstar, 30, told Us. "I learned a lesson. The whole world learned a lesson!"

Simpson was joined by fellow honorees Petra Nemcova, Lauren Conrad, Whitney Port, True Blood hunk Joe Manganiello, Rachel Zoe Project alum Brad Goreski, single-again Joe Jonas and Hayden Panettiere -- plus attendees Paris Hilton, Kim Richards and many more.

Joked Panettiere: "It's a trip for me to try to dress myself, [so] I couldn't possibly get an award for it!"

Watch all the stars let loose and talk fashion, Us Weekly and more in this exclusive video!