Ballerina briefs = panties.

I'm not sure why Elle featured a pair of panties as the bottoms to an outfit in the February issue. It wasn't a lingerie spread--the model was fully-coiffed, had on a top that was a top and not underwear (it was actually a rather lovely blouse that could have looked nice with real bottoms instead of panties--or, oh, sorry, a "ballerina brief"), and was wearing shoes, jewelry, and a handbag. Actually, most of the spread was very nice, but calling underwear a "ballerina brief" doesn't make it something acceptable to wear in public.

Unless you're Sienna Miller:

Actually, I take that back. Black tights or no, panties are never a legitimate bottom. Sorry, Sienna. We'll all remind you not to forget your skirt next time.