The pair have been on vacation together in St. Barts since Thursday, hinting at a possible romance across various Instagram photos taken during the trip.
On Sunday, Bieber posted on his Instagram account a photo of himself grabbing Baldwin slightly above her waist as the two stars locked lips for a romantic kiss.
The un-captioned photo was followed up by another snap of the two lovebirds enjoying a night out dressed fashionably and getting cozy together while laying down on a couch.
"He's just going through a time in his life where he's transitioning in a really positive way and he needs good people around him. And I'm trying to be a good friend and be there for him and support him," she continued.