19-year-old Sykes is said to have "been out on a few dates" with the goddaughter of the late Amy Winehouse and the couple were spotted being "very touchy-feely" at Nicki Minaj's Hammersmith Apollo gig on Monday (June 25).
"Nathan and Dionne have been out on a few dates but were keen to take it slowly," a source told The Sun. "Things have clearly stepped up a gear now, though.
"They were very touchy-feely at the show and didn't care who saw them. 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."
Sykes's bandmate Max George claimed earlier this month that the teenager recently got close to a 25-year-old porn star following a gig in Las Vegas.
"She said hello to him and two minutes later she took her phone out of her bikini bottoms," George explained. "They were hiding behind the curtains."
Watch The Wanted in the video for 'Chasing The Sun' below: