Katherine Heigl, Mandy Moore and Alicia Silverstone were all on hand for the opening of famed Australian designer Peter Alexander's flagship L.A. store Wednesday night -- and ET's Thea Andrews got the fashion 411 from the three lovely and talented actresses!

The star-studded event benefited animal rescue shelters Hearts United for Rescue and Kinder4Rescue.

Peter Alexander's L.A. flagship store promises an eclectic mix of ornate and modern fashionable loungewear for men, women and kids, plus gift and décor items including pet accessories.