Jennifer Lawrence played peek-a-boo in this daring Dior at the 88th Annual Academy Awards.

The Hidden Figures star slayed in a vampy, midnight blue custom Alberta Ferretti number.

Theron killed the red carpet this year in Dior as well.

Emily Ratajkowski stepped out in a plunging gown with a feather hem by Jonathan Simkhai.

One word sums up this floor-length champagne number from Stephane Rolland: Zowie.

The rising star wore a Tom Ford with a deep, plunging neckline to the 88th Annual Academy Awards.

The Irish actress looked stunning in this backless Calvin Klein gown.

Klum says she stitched up the cleavage on this Julien Macdonald gown by a few inches before leaving for the ceremony. Yeah, right.

This Zuhair Murad gown actually isn't as sheer as it looks, thanks to built-in cups. But still: Hot.

At the 87th Academy Awards, Margot Robbie wore a classic Saint Laurent gown kicked into high gear with sheer sleeves and a plunging neckline.

The model looked flawless in this whimsical Versace gown.

Theron wore this Dior gown to the Oscars in 2014 and took everyone's breath away.

Boy, does Elie Saab know how to bring out the sexy in a gal, right? This triumphant, sheer-paneled wonder is one of Saab's best.

Model Miranda Kerr looked sharp and sexy in this white Emilio Pucci gown.

The actress' backless Elie Saab gown came complete with a sexy slit, allowing her to show some leg on the red carpet.

The sexy singer flaunted a ton of cleavage in this printed Philipp Plein gown.

Officially, Chrissy Teigen can do no wrong on the red carpet. This Zuhair Murad gown is no exception.

Streisand claims she had no idea how sheer these Scaasi evening pajamas were. Mmmm hmmmm.

Sexy songstress Rita Ora wasn't afraid to show off her assets at the Vanity Fair after party in 2015.

The actress wore Saint Laurent and went brunette to complete a dark and dreamy look for the 2014 Oscars.

When the gorgeous actress stepped onto the carpet in this blinding Dior, it was one of the most memorable entrances in recent history.

The slit is so high on this black velvet Atelier Versace gown that it launched a meme and a Twitter feed called @angiesrightleg.

This Camilla and Marc look leaves little to the imagination...including what kind of underwear Jena likes.

If you look closely (and you know you want to) you'll see a sheer panel just below the, um, chest area. So this slinky Armani Privé gown reveals a (little) less than you think.

We'll just say it: Baby got back, thanks to the plunging rear side of this navy Guy Laroche gown.

Rosie Huntington-Whiteley demanded attention at the 2015 Vanity Fair after party in this elegant emerald gown.

Black stretch pants. Bedazzled loincloth. Black chain-link top. Feathered headdress that's one and a half times taller than Cher's head. Sexy or scary? Take your pick.

"Should have worn a bra," is how Paltrow has summed up this Alexander McQueen gown.

This may be the celeb's sexiest red carpet look to date.

Backless was hot at the Oscars in 2015, and Naomi Watts wore the trend well.

Fitted black Versace gown, black hair extensions--who knew Morticia Addams could look so hot?

The Gone Girl star looked red hot in this Givenchy Haute Couture gown.

The singer was all glam at the 87th Academy Awards.

At the after parties, stars can slip into something a bit more comfortable than their awards show attire. In Jennifer Lopez's case at the 2015 Vanity Fair post-Oscars party, that something was also much sexier.

Actress Lily Collins' after party gown was sheer in all the right places.

Not only did the star reveal some side boob in this silver wrap Alexandre Vauthier mini-dress, she flaunted a whole lotta leg too.