The two were spotted getting close at a Kings of Leon concert in Amsterdam on Saturday, Us Weekly reports.
A concertgoer named Millie Janssen told the outlet that the singer and "Game of Thrones" star "kissed and cuddled" at the concert, which was a pre-MTV European Music Awards show.
"He had his arm around her as they walked in, and then he was holding her before the show," Janssen told the outlet. "Joe and Sophie kissed a few times and were talking and drinking soda."
There's even photographic evidence of the two cozying up in the stands:
Jonas and Turner were reportedly seated with the former's DNCE band mates, but Us notes that didn't stop them from packing on the PDA. Janssen told the magazine the two "were dancing together and singing along" to the music.
"Joe would kiss her cheek as they danced next to each other," she said, adding they "appeared very into each other."
Jonas and Turner reportedly first hung out together around Halloween. They appeared in a friend's Instagram post dressed up for the occasion ― with Jonas as a Dalmatian and Turner as a bunny.
Jonas has previously dated Demi Lovato, Gigi Hadid and Ashley Greene. The JoBro opened up about his relationship with Greene in a Reddit AMA in October, revealing he lost his virginity to the "Twilight" actress.