Sandra Bullock [1]'s 5-year-old son may be going as a ninja turtle for Halloween [2], but he had other ideas for his stylish mama. The actress showed up to The Tonight Show [3] in a trendy navy and black Jonathan Simkhai midi dress that featured a mesh peplum hem and white embroidery. Her formfitting outfit, which she completed with strappy Stuart Weitzman stilettos, showed off her toned body, proving that the 51-year-old just doesn't age — but can she pull off a "slutty" Batgirl costume [4]?

Sandra hilariously explained to Jimmy Fallon [5] that her son selected the look from a "sensible catalog," pointing to it and exclaiming, "Mama, you has to wear this!" Read on to watch the clip and hear the star describe the Halloween costume, which consists of a leather miniskirt, over-the-knee boots, and bustier so small "you can barely tell it says Batgirl." Then, once you've got a smile on your face, scroll to see Sandra's fashionable ensemble [6], of the subtly sexy variety.

Sandra showed up to The Tonight Show in a sleek navy and black midi by Jonathan Simkhai [7].

Sandra's netted peplum hem met a pair of black strappy Stuart Weitzman stilettos.

Sandra pinned back her loose waves, showing off her dress's high-neck silhouette.