Finding the perfect outfit is such a struggle that celebrities aren’t even bothering anymore; they’re just going out in their bras.

Basic bras have replaced the corset, the pajama shirt and the slip as the underwear-as-outerwear trend du jour.

Just take a look at Sunday’s Billboard Music Awards red carpet, where a large amount of attendees eschewed — or just forgot — their tops. Also this week, Kristen Stewart rebelled against the glam dress code at the Cannes Film Festival, showing up for a premiere in a wan bandeau. Meanwhile, back in La La Land, celebs regularly are spotted exiting the gym or going out for lattes in glorified sports bras.

Now, there’s nothing wrong with showing some skin. Madonna long ago proved that showing one’s bra strap was a style statement and not a faux pas. Designers Vivienne Westwood and Jean Paul Gaultier transformed the corset from a much-maligned undergarment to the ultimate punk-rock feminist top. And Sarah Jessica Parker confidently rocked all manner of transparent tops, satin briefs and bandeau tops during her tenure on “Sex and the City.”

But wearing a Gap-level basic bra in lieu of a shirt isn’t sexy or provocative. It has none of the manic glee of Miley Cyrus’ surreal club-kid outfits, or the in-your-face provocation of Jane Birkin in a see-through dress, or the offhand dishabille of Kate Moss in a slip.

It’s just lazy. It’s the equivalent of wearing leggings outside of the gym or going to class in pajamas.

Just contrast those underdressed starlets at the Billboard Awards with the night’s honoree, Cher. The 71-year-old legend also indulged in some underwear-as-outerwear Sunday night, but her spangly see-through body stocking, beaded negligee and sequinned heart-shaped pasty were the opposite of Halsey’s unfabulous Victoria’s Secret castoff.

It was fun, it was flashy and, most importantly, it was a real outfit — not a half-assed, half-complete attention grab.