Hailey Bieber let loose at Kylie Jenner’s 29th birthday party.

The Rhode founder attended her close friend’s birthday bash Friday, and reposted a wild shot of herself licking a female friend’s backside on her Instagram Stories.

The original shot was posted by influencer Devon Lee Carlson, and shows Bieber bent down and licking her friend’s left side while wearing a tiara, as the friend — whose face isn’t shown — is bent over a marble counter and holds a drink.

The friend’s hot pink sparkly thong was visible thanks to her low-rise jeans and crop top.

Bieber, 29, reposted another Instagram Story Saturday from Carlson’s sister, Sydney Lee Carlson, of herself wearing a pink feather boa and dancing while shaking a cocktail shaker.

Sydney captioned the party footage, “The @haileybieber special.”

Jenner, whose birthday is on Aug. 10, celebrated her big day early with family and friends. The makeup mogul posted snaps from her party on her Instagram Stories, including one of her in a skintight, hot pink minidress and matching feathered heels.

Jenner also showed off her three cakes, which included a pink bikini-themed creation and one bedazzled with colorful gems.

Her sisters Kim and Khloé Kardashian were spotted arriving at the party in Beverly Hills, California, as well as Hailey’s husband, Justin Bieber, in pics obtained by the Daily Mail.

There were no shots of Jenner’s boyfriend, Timothée Chalamet, at the party, whom she’s been dating since January 2023.

On Saturday, Hailey also posted a carousel of new pics, which included video of her working out and a shot of her rocking a bright yellow bikini

The model showed off her perfect form while doing weighted squats, and another pic showed off her toned stomach in a crop top as she laid in the sun with a big smile on her face.

She captioned the post, “August so far.”