Unfortunately, it's the sort of thing you learn the hard way: even black bottoms can be sheer.

Mena Suvari stepped out on Monday night, all dolled up for a screening of "American Reunion" in London. But when the star bent over to autograph some photos for her fans, her gauzy black dress might have revealed a bit more than she intended (we think -- then again, wardrobe "malfunctions" seem more and more purposeful these days).

It was rather unfortunate, considering we're totally digging the LBD otherwise. The drape in the back and the inset pattern on the front are both super chic, as is Mena's tasteful updo.

(On another note: who knew Mena had such a giant tattoo on the back of her neck?)

See Suvari's possible wardrobe mishap (and more celebrity clothing malfunctions) below.

PHOTOS:

See more celebrity wardrobe malfunctions!

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  • Britney Spears

  • Nicki Minaj

    October 2012

  • Emma Watson

    (Splash News)

  • Joely Fisher

    June 2012

  • Soo Yoo Jin

    2012

  • Olga Sorokina

    December 2012

  • Valentina Lodovini

    2011

  • Stella Tennant

    2011

  • Jennifer Lopez

    (Pacific Coast News)

  • Kourtney Kardashian

    (Flynet)

  • Kourtney Kardashian

    (Flynet)

  • Jennifer Lopez

    (Pacific Coast News photo)

  • Sofia Vergara

    (Splash)

  • Katy Perry

    (Pacific Coast News photo)

  • Miley Cyrus

    (x17online.com)

  • Kim Kardashian

    (PCN)

  • Kate Moss

    (Flynet photo)

  • Kate Moss

    (INFDaily.com photo)

  • Kate Moss

    (INFDaily.com photo)

  • Kim Kardashian

    (Instagram)

  • Kim Kardashian

    (Flynet photo)

  • Kim Kardashian

  • Micaela Schaefer

    (WireImage photo)

  • Lisa Rinna

    (Getty Photo)

  • Arta Dobroshi

    (Getty photo)

  • Mariah Carey

    (Getty photo)

  • Kanye West

    (Splash News photo)

  • Dakota Fanning

    (Flynet photo)

  • Chloe Sevigny

    (WireImage photo)

  • Amanda Lepore

    2011

  • Melody Thornton

    (Getty Photo)

  • Adrienne Bailon

    (Getty photo)

  • Miley Cyrus

    (AKMGSI photo)

  • Rona Hartner

    (Getty)

  • James Corden

    (Getty)

  • Paula Abdul

    (Getty)

  • Lacey Schwimmer

    (Splash)

  • Amy Smart

    (Splash)

  • Brooke Mueller

    (Getty)

  • Phoebe Price

    (Splash)

  • Lady Gaga

    (Splash)

  • Taylor Swift

    (Splash)

  • Gwyneth Paltrow

    (Splash)

  • Keke Palmer

    (Splash)

  • Kelly Rowland

    (Getty)

  • Josh Hopkins

    (Splash)

  • Blake Lively

    (Getty)

  • Courtney Love

    (Splash)

  • Lauren Conrad

    (Getty)

  • Kate Middleton

    (Getty)

  • Demi Lovato

    (Splash)