Equinox gym, which is known for using highly sexualized ads to attract new members, is gaining lots of attention online for its ad showing a mother breast-feeding at a restaurant as part of its #CommitToSomething project.

The woman in the ad is 31-year-old heiress Lydia Hearst, who is wearing flashy earrings in an apparently fancy restaurant as she breast-feeds twin babies. Many have noted the peculiarity of this ad, as Hearst is not a mother herself and it's difficult to find a connection between exercise and breast-feeding.

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Advertising agency, Wieden + Kennedy New York created the #CommitToSomething ads for Equinox, which set out to highlight socially relevant themes for the project. One ad for the project shows a female activist standing up for her cause and another includes "a male cheerleading champion who wasn't threatened by a stereotype," according to Equinox. Fashion photographer Steven Klein, who also photographed Kylie Jenner in her controversial Interview magazine wheelchair shoot, shot the series of #CommitToSomething ads in Los Angeles.

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"It is the responsibility of advertising to communicate modern times and social issues," Klein said in a statement. "This campaign addresses today's issues and social commentaries, which is a powerful approach instead of portraying people as superficial objects with no narrative."

Equinox CMO Carlos Becil reiterated the campaign message of commitment to AdFreak.

"It's not just about fitness - it's about life," Becil said. "The concept of commitment is bold, incredibly powerful, and it's real, especially in a world today where commitment is lacking."

What people are saying about the ad.

Reactions to the image have been mixed. While some have praised the ad for seemingly trying to normalize breast-feeding, others have criticized it for being exploitative:

When one commenter wrote on Equinox's Facebook page that it would be "disrespectful" to breast-feed at a fancy restaurant as the ad depicts, Equinox responded with a humorous line, "Try explaining that to an infant." Equinox told another commenter that parenting doesn't stop when a mom goes to the gym, therefore breast-feeding in front of others shouldn't be an issue.

Equinox Facebook page - facebook.com

Coincidentally, one Twitter user complained of seeing a woman breast-feeding outside Equinox last year:

The broader conversation about breastfeeding.

The breastfeeding ad comes at a time when mothers face immense scrutiny for breast-feeding in public. Over the past year, there have been countless online movements to normalize breast-feeding, which actress Alyssa Milano has famously championed many times. In 2015, she posted a few Instagram photos of herself breast-feeding her baby and was surprised to receive backlash for doing this.

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"I think people are more comfortable sexualizing breasts than relating them to what they were made for, which is feeding another human," Milano told Entertainment Tonight in September.

Milano wrote in a September TIME article that "normalizing breast-feeding" is the solution to desexualize breasts and recognize that they exist to feed another human being rather than just to turn someone one.

"Yes, they’re pretty," she wrote. "And yes, they have a purpose in women’s sexuality. But their main purpose is to feed another human."

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Watch ATTN:'s video below explaining why 2015 was the year of the breast.