She showed off her curves and tight tummy while singing along to the Sam the Sham & The Pharaohs hit.
"Big mood," she wrote in the caption of the video, tagging her swimwear line, Inamorata.
Many of her 17.4 million followers drooled over the sun-soaked video, leaving compliments like "Stunning" and "Beautiful" in the comments section.
The belly-baring video puts to rest pregnancy rumors following Ratajkowski's surprise wedding to Sebastian Bear-McClard in February and a cryptic Instagram post earlier this month. She also denied the pregnancy rumors herself, telling USA Today that her followers simply misconstrued her meaning behind the caption.
In the Instagram photo in question, Ratajkowski sat in an orange tree holding one of the plump fruits in front of her abdomen.
"Bearing fruit," she wrote in the caption, leading many fans to take the post as a subtle message that she was expecting. But she quickly laid that rumor to rest at the I Feel Pretty premiere earlier this month.
"I wasn't thinking of that when I posted it," Ratajkowski told USA Today. "That's really sweet that people were so excited. I'm not pregnant."
Ratajkowski confessed that she thought she was being clever with the caption, and didn't expect it to be misconstrued.
"I was in a tree holding fruit. Instagram captions are not the easiest thing to come up with. And it seemed like the right one," says Ratajkowski. "I was bearing fruit."
The Gone Girl actress shocked the world and defied convention by announcing her secret wedding through her Instagram story back in February. She and her husband, Bear-McClard, hadn't even publicly confirmed their relationship yet, though they had been seen together on Valentine's Day in an unmistakably romantic context.
"Soooo," she wrote in one Instagram story, continuing into the next, "I have a surprise. I got married today."
Since then, she has received even more skeptical comments about her Instagram posts, which are often revealing and racy. Ratajkowski says that being promiscuous on Instagram doesn't make her a bad feminist.
"If anything, I wish the conversation was more wide-ranging rather than the same, 'How do you have an Instagram with lots of bikini snaps and still call yourself a feminist?' I'm like, that's the kind of question I'm sick of answering, but I'm not sick of feminism or Instagram," Ratajkowski told Vogue U.K. last summer.