Hailey Bieber is delivering mermaidcore.

The model, 26, shared some sexy snaps on Instagram yesterday in a very “Little Mermaid”-inspired dress, showing off her back muscles in the low-reaching mini.

“and after,” she captioned the post, adding three fish emojis and tagging photographer Tyrell Hampton in a series of four photos showing off the backless ‘fit that she wore to Beyoncé and Jay-Z’s annual Oscars afterparty on Sunday.

Mrs. Bieber posed on a tan chair, showing off the lace-up back of her seafoam green Valentino Haute Couture dress covered in iridescent paillettes — which give the look a scale-like quality — and a pair of black bow-trimmed heels, also from Valentino ($1,150).

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Hailey Bieber rocked an underwater-themed Valentino dress at Beyoncé and Jay-Z’s Oscars afterparty as rumors of her feud with Selena Gomez continue to swirl.haileybieber/Instagram

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Bieber sported a sassy Valentino dress in the photos.haileybieber/Instagram
She kept the wraparound diamond earpiece by Ana Khouri she wore to the Vanity Fair Oscars party earlier in the night and sported a red manicure with a simple, straight hairstyle in the photos, leaving the dress to do the talking.

“Lil Mermaid,” her stylist, Karla Welch, commented on the snaps, sharing several photos on her own Instagram Story and tagging Valentino’s creative director, Pierpaolo Piccioli.

Christine Quinn agreed with the Disney princess energy, adding a mermaid emoji and writing “vibes.”

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She accented her mermaid-esque dress with sparkling earrings.haileybieber/Instagram
While her outfit definitely made a statement, the bulk of the comments section was focused on her feud with Selena Gomez, 30.

The latest beef — which involves Hailey’s pal Kylie Jenner and some eyebrow photos on social media that seem to be making fun of Gomez — has fans of the two stars pitted against each other.

“So pretty,” one Instagram follower wrote. “We shouldn’t judge people who we don’t know. Nobody knows the whole and detailed story but them. Hopefully that someday the world stop confronting woman vs woman.”

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Bieber and Gomez posed for a photo together last fall after attempting to debunk rumors of their feud.Tyrell Hampton

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Selena Gomez’s fans spoke out in the comments section about Bieber’s alleged “mean girl” behavior.Instagram/ Selena Gomez
While many of the comments supported the Rhode skincare founder, plenty of haters entered the chat, too.

“i thought something smelt fishy,” one Instagram user wrote, while another added, “We don’t forget what the mean girls did.”

As for the “Baby” singer, 29 — who proposed to his now-wife just months after splitting from the “Only Murders in the Building” star in 2018 — he supported his wife on social media amid the feud before creeping into the Vanity Fair Oscars party wearing a blanket Sunday night.