Ariana Grande and Niall Horan are probably on their way to being besties.

On June 3, Grande was spotted leaving the One Direction member's house at 3 AM after spending five hours inside, Daily Mail claimed. The petite songstress was seen departing Horan's Hertfordshire mansion with a few guys, who are probably part of her entourage team. She was picked up by a driver and a bodyguard.

Hollywood Life has reached out to Grande's representatives for comment, and the songstress' camp said, "Ariana is friends with Niall. He had a big party that she was leaving." No statement from Horan's team has been made public yet.

This news comes after Grande and Horan spent time together at the London burlesque club Cirque Le Soir, where the two partied with friends until the wee hours of the night, Hollywood Life noted.

A separate report from Daily Mail wrote that Grande's ex-boyfriend, Nathan Sykes, was also present in the scene. At past 3 AM, the recording artist and her companions left the club with the 21-year-old singer carrying a lilac helium balloon.

The former Nickelodeon star is in London to jumpstart the European leg of her Honeymoon World Tour, Hollywood Life reported. Horan was in attendance at Grande's sold out concert in the O2 Arena and openly admired the pop star's vocal prowess as she sang "One Last Time."

On Instagram, he posted a video of Grande performing and captioned it: "This girl blew me away! She has the most incredible voice I've heard! Superstar!"

As it turns out, Grande wasn't completely oblivious to Horan's appearance at her concert. Hours after the show, the "Love Me Harder" singer shared a short clip on Instagram hanging out with Horan. The video featured the two artists inhaling helium balloons and talking in a chipmunk-sounding voice. The only comprehensible sentence in the recording was Grande saying, "I can make a broke b*tch rich."

Grande and Horan are both single. The former broke up with her boyfriend of eight months, rapper Big Sean, last August due to busy working schedules, Daily Mail noted. Independent, on the other hand, has reported that Horan has split from Australian student Melissa Whitelaw, who he was romantically linked with since February.

According to Independent, the long distance between each other proved to be difficult for the 21-year-old singer's budding relationship with the model. Horan had a break from One Direction's On the Road Again Tour from April to May. The concert series will commence once again on June 5 in Cardiff, Wales.

Grande, meanwhile, is gearing up to delight her fans once again with a third album called "Moonlight," Music Times reported. The record's name was revealed by the songstress in a Twitter direct message with a fan. In the DM, she confirmed that "Moonlight," a phrase she has been using a lot lately on her social media accounts, is the title of both of a new song and the upcoming album.