The two singers have yet to confirm their relationship, but that didn't stop them from showing off their love during a steamy, secret vacation in the Bahamas together.
The two were caught getting super touchy while partying on a yacht on April 10.
The "Slow Hands" singer was even seen kissing the 21-year-old's cheek as he wrapped her arms around her neck!
Their secret Bahamas getaway wasn't their only vacation together. The pair was also spotted just a few days before in Augusta, GA, where Niall was attending the 2018 Masters Golf Tournament.
As OK! readers know, rumors first started swirling that the pair was an item after they were snapped packing on the PDA during a Backstreet Boys concert in Las Vegas, back in February.
And since then, the two have been getting pretty close. The "Love Myself" singer flew to London last month to support her rumored boyfriend, she even hit the stage during his concert to sing a duet with his opening act, Julia Michaels.
Nial and Hailee reportedly first met when they both performed at the Jingle Ball tour in December.
What do you think of Niall and Hailee dating? Sound off in the comment section.