We've seen enough wardrobe malfunctions to know how they often happen (a sheer top, a too-short bottom and not enough undergarments, to name a few).

A top simply falling off, on the other hand, is a rare sight. Katy Perry came close last night when she walked the ASCAP POP Music Awards red carpet in an ethereal Temperley London gown.

The dress itself was tasteful and elegant. Katy's wandering strap, however, just left us nervous. From the runway pic (below), you can see that both straps are supposed to go over the shoulder. Yet the purple-haired pop star kept the left strap slung down, tugging at the dress and revealing more chest than necessary.

Why look so messy, Katy? Why risk a wardrobe malfunction when the dress (and your hair) is eye-catching enough?

Luckily, Perry seemed to make it across the red carpet without losing her second strap. Malfunction averted.

PHOTOS:

See (real!) wardrobe malfunctions from your favorite celebs:

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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)