Zac Posen was responsible for some of the most impressive (and winning ) gowns at Saturday night's SAG Awards . These award show getups tend to involve a designer's absolute freshest looks (often not even available for sale yet), and the dressings are planned well in advance. But one Zac Posen dress cameo came as a pleasant surprise to the designer.Demi Moore skipped the ceremony's red carpet. But when she appeared on-stage later in the evening to present the award for Outstanding Performance by a Cast in a Motion Picture, she was wearing a short-sleeved, ruffled-skirt Zac Posen shirtdress gown from spring '03 — the designer's second collection , ever.Posen was thrilled to see the actress, who was styled by Brad Goreski for the event, in one of his early designs, especially since it apparently came from Moore's personal archive (read: her closet). "The unbelievably beautiful #DemiMoore wearing her own #ZacPosen gown made in 2002 at the #SagAwards tonight," he wrote on Instagram adding that she had been saving it "for the right moment." He also posted a video of his creation in action, with the ruffles floating on-stage.