We call this one “All Wet In London.”

Sienna Miller experienced a “Fergie-style” photo-op nightmare when she showed up at the photocall for G.I Joe: The Rise of Cobra at London’s HMS Belfast on Wednesday with soaking wet pants.

Don’t be alarmed, no bladder control issues her. The bed-hopping vixen’s wet backside is being blamed on the fact that the cast arrived via boat — Sienna was splashed as she exited the tiny vessel.