We're having a serious old Hollywood flashback!
The Rum Diary actress dazzled in this vintage tulle and sequin design, pairing it with Casadei platform pumps, simple jewelry, and a much tamer hairstyle from what she was rocking later in the weekend!
Although we love this homage to glamour of years past, we think Amber would've looked totes better in something a bit tighter.
Her killer figure just simply isn't being showcased in this billowy design!
Ch-ch-check out more pics of her dress (below!)
[Image via FayesVision/WENN.]