rumer_willis_022514.jpgGetty Images for Vanity Fair

Last night was all about the boobs when both Stacy Keibler and Rumer Willis highlighted their fun bags at Vanity Fair's Young Hollywood at hotspot No Vacancy on Tuesday night. Stacy almost suffered an embarrassing nip slip when her low-cut bubble-gum pink suit gaped and almost exposed her full breast. And we still can't tell if Rumer is wearing pasties or if she went totally braless -- either way the geometric Hernan Lander look is eye catching!

At one point, George Clooney's former flame pointed out her lack of undergarments, saying, "I'm not wearing lingerie." We can't tell a lie -- we think this cheap-looking, ill-fitting suit does absolutely nothing for the leggy lady.

A bevy of celebs including Jessica Lowndes, Cobie Smulders, Bella Thorne, Jamie Alexander, Kate Mara, Jenna Malone, Keirnan Shipka, Maggie Grace and many more joined the cleavage-flashing ladies for the glittering soiree, which was hosted by hottie Chris Evans.

Hollywood offspring Zoe Kravitz and Steven Speilberg's daughter Sasha both donned black dresses for the bash.