The 27-year-old singer has been dating Brazilian model Daiane Sodre since the summer, and the two are now "getting serious," a source close to Sodre tells ET. However, they're not ready to make their relationship public yet, the source adds.
"They're both really happy and see each other as often as possible," the source says. "She's playing it cool though and happy to take it slow."
Jonas and Sodre have been photographed out and about together before. The two were snapped going out for lunch at Sweet Butter Kitchen in Studio City, California, in July.
According to the source, Sodre is also a big hit with Jonas's pals and DNCE bandmates.
"She gets along with his friends and the band -- everyone seems to like her!" the source notes.
So far, Jonas and Sodre have remained quiet on social media about their relationship. However, in August, the model congratulated DNCE on Instagram for their Best New Artist win at the MTV Video Music Awards.
Sodre is an in-demand model, having starred in campaigns for Victoria's Secret, J. Crew, and Nasty Gal, to name a few.
.... Just don't expect any over-the-top displays of affection from Jonas anytime soon.
"No, not at all," he told Women's Health last month when asked whether or not he's into PDA. "Look, when you really like somebody, that kind of goes out the window. But even around friends and stuff, I think you keep that for the bedroom or behind closed doors."
"Especially at the beginning of the relationship, you've got to be cautious of that," he added.
"I don't know. I think life's too short, you know?" he told ET exclusively. "I mean, ultimately, I think of myself as an honest guy. There are just those moments in life where you have to be true to yourself and true to the world."
"I'm not out to hurt anybody, but I think, ultimately, I'm just telling my stories and what I can say from my heart," he added.