When her swimwear ad for the 2015 Sports Illustrated Swimsuit Issue was revealed on Feb. 4, Ashley Graham made history by becoming the first plus-size model to appear in the magazine's annual edition of bikini-clad women.

The model, who loves her curves, is featured in a sexy, black string bikini in the ad. She posted the advertisement to her social media accounts early Thursday.

"Secrets out!! So honored to be the face of #CurvesInBikinis," the caption said.

The ad is part of online retailer swimsuitsforall.com's campaign aimed at encouraging women of all body types to feel confident and sexy in swimwear, Us Weekly reports.The swimwear retailer, who offers its Swim Sexy line bikinis in sizes from 10-34, is using the hashtag #CurvesinBikinis to promote its positive, body-loving message in social media.

"The world is ready for more curves in bikinis," Graham says of the campaign.

The Lincoln, Nebraska native has been modeling since age 12. She is best known as a Lane Bryant lingerie model and has appeared in Levi's campaigns and graced fashion magazines such as Latina, Vogue, Harper's Bazaar and Glamour.

Comments on the swimsuitsforall Facebook page have been very supportive of the campaign and magazine ad featuring Graham. Many commenters have said that they don't think Graham is really plus-size, but rather "normal size."

Meanwhile, the television ad, which features three slender and muscular hunks gawking at Graham, has caused its own controversy.

"So, if she represents the average woman, why are the male models not representing the average man?" Noelle Bartl wrote on the Facebook page,

The IMG model has admitted her body is not perfect, but that doesn't take away from its sex appeal.

"It's cellulite city back there," Graham told Huffington Post in August.

When it comes to photo retouching, Graham is okay with it -- in moderation.

"I'm thankful that they take that out for photo shoots," she said. "A little bit is fine, and there's a time and a place for it. On the other hand, if you're forming my body into something it's not, I'm not okay with it."

This is not the first time Graham has made headlines. Her 2010 sexy lingerie commercial for Lane Bryant was reportedly banned from ABC and Fox, which infuriated Graham.

"The Victoria's Secret girls can flaunt around their panties all day long, but when there's a bigger woman with a little bit extra, they snipped it out immediately," she told WPIX in 2010.

Fox agreed to air the ad during the last 10 minutes of "American Idol" following public backlash and criticism from the plus-size company.

The Sports Illustrated swimsuit issue will be released Feb. 9.