The blonder than blonde heiress, who recently launched a Marilyn Monroe-inspired perfume, was snapped by paparazzi while shopping at L.A.'s aptly named Trashy Lingerie shop, which stocks items like the $400 Alice in Undie Land costume and the naughty lamb-clutching Bad Peep outfit for $350.
Although most folks don't shop for costumes while wearing a costume, Hilton did just that, sporting a white-and-navy-striped bustier top, navy hot pants, and a white sailor cap while she scanned the shop's aisles for more sexy options and held a few keepers in her hands.
Knowing how hard Hilton likes to party, it's not a total surprise that she couldn't wait until next weekend to start celebrating the holiday or that she will need more than one costume for the occasion.
What do you think of her sailor girl getup? Let us know in a comment below.
In related news, check out some of the hottest Halloween costumes for 2010.
And while you're at it, check out the most inappropriate Halloween costumes of all time.