Niall Horan, who was recently spotted enjoying a night out with Ariana Grande in the U.K., has reportedly split from girlfriend Melissa Whitelaw.

The One Direction member reportedly first met the 21-year-old Australian student in February at a casino, where his band was on the "On the Road Again" tour.

"OMG Niall Horan and Melissa. They were seen in a casino, they kissed," an eyewitness tweeted at the time, via Daily Mail. "And he held her by the waist and playing with her hair."

Although Whitelaw and Horan were "really close and had fun whenever they went out together" during their low-profile romance, they supposedly could not continue their long-distance relationship.

"But realistically, they always knew it was going to be tough, keeping a relationship going with such distance between them," a source revealed to The Sun, via MTV UK.

Meanwhile, the Irish star watched the "One Last Time" singer perform at the O2 Arena on Monday evening -- her first U.K. date for "The Honeymoon" world tour.

According to The Mirror, the two met each other backstage.

Shortly after her sold-out gig, Grande headed to central London's burlesque club Cirque le Soir with a small entourage of pals. Horan then joined her, and they partied together until early Tuesday morning.

The pair left separately just before 3 a.m., seemingly interrupted by three fire engines called to the venue due to an electrical fault.

The "Break Free" crooner also took to her Instagram account on June 2 to share a video clip of herself inhaling helium gas from a balloon and giggling with the "Midnight Memories" hitmaker and her friends.

However, sources close to Grande insisted to TMZ that her recent encounter with Horan "was anything but intimate," adding that her manager Scooter Braun and both of their entourages were also present.