The pair outed themselves as a fully fledged couple when they were snapped canoodling in the ocean during a romantic holiday.
Dionne - goddaughter of the late Amy Winehouse - couldn't keep her eyes off her boybander beau as they made a splash on the island of St Vincent, while staying at the Buccament Bay resort.
After the pictures hit the press, Nathan took to Twitter to seemingly confirm the romance.
"Rule #1 nothing is private in the music industry haha," he said.
The couple were said to have 'gone public' in July, when they were spotted snogging at a gig.
A source told The Sun at the time: "They’ve known of each other for a long time, they went to the same school and Dionne supported the group on a few of their festival gigs last year."
We think they make a lovely pair.