Well, the dress has been found ... to be a fake!
The thief who took the gown says he took the dress from Lupita's room at The London after finding the door ajar.
[Image via WENN.]
The British beauty looked impossibly immaculate in a dusty rose Gucci strapless gown with back slit and tiered ruffle layers at the bust.
Ruffles can be tricky, but this is outstanding!
Miz Beckinsale accessorized with a gold Neil Lane choker, matching gold Judith Leiber clutch, Brian Atwood heels, and an updo with face-framing wisps.
[Image via Daniel Tanner/WENN.]