Katie Holmes Looks Pretty In this Dress

Katie Holmes -- who's supposedly single and loving it -- returned home to her New York apartment building Tuesday night with her LBD partially unzipped! Which leaves us wondering ... who's the lucky man?

Ahh, we jest -- the actress attended a launch party for her cover of DuJour magazine in a pleated black dress -- somewhat see-through with her lacy black bra showing. The usually-conservative fashionista took a risk with this look and we love it! Even the unzipped zipper! Uh ... wardrobe malfunction, Katie?