The singer, 21, didn't caption the affectionate snap, but he followed it up with another pic that showed him and the model, 19, cozying up on a sofa.
The pair are on a tropical New Year's vacation in Anguilla and have been sharing photos of their getaway, which isn't the most romantic trip, as guests also include Bieber's father and siblings.
On Friday, January 1, Baldwin, who's the daughter of actor Stephen Baldwin, also posted a pic that showed her with her arms wrapped around the "Sorry" singer's neck and shoulders.
This isn't the first time they have been spotted getting close — they partied together at a private island near Grenada for the pop star's 21st birthday last February.
As Us Weekly reported exclusively, Bieber has recently been hooking up with Kourtney Kardashian.
The teen heartthrob has denied in the past that he and Baldwin are a couple, and told Billboard in November that she is "one of my best friends in the entire world."
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