A clothing brand that is usually the butt of jokes just got a massive endorsement for free

Loft - Ann Taylor's casual and inexpensive sister brand - is known for its conservative clothing.

But one major celebrity has recently expressed she's a fan of the company's attire.

Lena Dunham, executive producer and star of HBO hit show 'Girls,' posted a photo of herself on Instagram donning a Loft outfit she says she wore for three days in a row.

"Been in the same outfit for going on 3 days - Ann Taylor Loft shirt & shorts from a very unexpectedly fruitful trip through their doors (must I stop making Ann Taylor jokes?)," she writes. 

"This is not an ad for Ann Taylor Loft," she adds. 

But even though Dunham's post wasn't officially an ad for the women's chain, it certainly could help the brand.

"We loved it," said Michelle Horowitz, Senior Vice President of Marketing at Loft, to AdWeek. "Often, we are at the butt of some comedian's jokes, and Lena has often teased us. We appreciate humor and see the levity in that and don't take it too seriously. We didn't ask her to do this. We knew nothing about it."

Loft has been trying to attract younger customers.

The retailer is traditionally seen as an uncool brand for older women.

In 2012, Ann Inc. President Kay Krill told Bloomberg she wants people to think of "fun, engaging, girlfriends, happiness," when they think of the brand. 

Recently, it was announced that mega company Ascena would be purchasing Ann Taylor's brands.