To be young, beautiful, and in love!

Demi Lovato and her longtime boyfriend, Wilmer Valderrama, were spotted taking a dip in the ocean in St. Barts on Wednesday, clearly enjoying some couple time. Demi, 23, and Wilmer, 35, weren't shy about embracing and kissing in the water, and appeared more in love than ever.

WATCH: Demi Lovato on Rumors Wilmer Valderrama Will Propose Next Year -- 'You Gotta Ask Him!'

The "Confident" singer also flaunted her super-fit bod in a sexy black one-piece swimsuit, looking flawless in the hard-to-pull-off style.

"Wilmer and Demi could not keep their hands off each other," a source tells ET. "They looked really happy and super affectionate."

ET confirmed on Wednesday that Demi is currently in St. Barts for the Victoria's Secret Swim Special airing in 2016, which her pals, Nick and Joe Jonas, are also appearing in. Demi took to Instagram to share photos of the three of them posing with the gorgeous models.

She also confirmed her boyfriend joined the trip, apologizing to Nick for "third wheeling" him. "I love these pics so much... Sorry @nickjonas for third wheeling you but your bromance third wheels me too!!! ? #somethingbigiscoming16 #CONFIDENT #myboys #baes," she wrote.

We doubt Nick minded too much. Wilmer and Nick are friendly with one another, and even smoked cigars together while the three hung out on the beach, our source tells us.

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ET caught up with Demi earlier this month at Billboard's 10th Annual Women in Music event in New York City, where she talked about possibly taking the next step in her relationship with Wilmer in 2016.

"You gotta ask him!" she said when asked if next year could be a potential engagement year for the couple. "I have no idea."

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