Ariana Grande and Niall Horan continue to fuel dating rumors, as they were recently spotted partying together in Barcelona, Spain.

According to HollywoodLife, the couple arrived separately at the Botafumeiro restaurant on June 15 to celebrate the 26th birthday of their mutual friend, videographer Alfredo Flores.

Grande and Horan each took to their Instagram account to send their best wishes to the birthday boy.

Happy birthday to my amazing friend @alfredoflores ! Turn upppppppp A photo posted by Niall horan (@niallhoran) on Jun 15, 2015 at 3:55pm PDT

 Havin it.... @alfredoflores @brilovelife @jonescrow

A photo posted by Niall horan (@niallhoran) on Jun 15, 2015 at 4:08pm PDT

Only way to celebrate @alfredoflores is the king ! A photo posted by Niall horan (@niallhoran) on Jun 15, 2015 at 5:38pm PDT

The "One Last Time" singer and the One Direction member first sparked romance speculation earlier this month when they were seen enjoying a night out together in England.

According to The Mirror, Horan watched Grande perform at the O2 Arena, as part of her first U.K. date for "The Honeymoon" world tour. The two met each other backstage.

Shortly after her sold-out gig, the "Break Free" crooner headed to central London's burlesque club Cirque le Soir with a small entourage of pals. The 1D member then joined her, and they hung out together until the next 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.

Grande also Instagrammed a video clip of herself inhaling helium gas from a balloon and giggling with Horan and her friends.

However, the "Problem" hitmaker recently made it clear that she refuses to be identified based on a man.

"A girl can be friends with someone with a d**k and not hop on it," she told The Sun, via Daily Mail. "I'm tired of needing to be linked to a guy. I'm not Big Sean's ex, I'm not Niall's new possible girl. I'm Ariana Grande."