Selena Gomez and Charlie Puth hooking up

Selena Gomez and Charlie Puth have been "hooking up", according to a new report.

The pair collaborated on the song We Don't Talk Anymore for Charlie's debut album Nine Track Mind and have remained close friends ever since. It seems there could be more to it though, with Us Weekly alleging the pair are more than just pals, and have been enjoying a fling over the past few months.

"It's not serious, but she's super into him," a source told the publication.

However, a friend of Selena's when asked about the relationship between the two singers insisted it's simply a "flirty friendship".

Whatever the state of their relationship, both Selena and Charlie have been very vocal about their admiration for one another.

"I don't know if anyone really understands me," Charlie told Us Weekly back in November (15). "Which is why I hang out with Selena Gomez. She gets me."

He first met Selena at a MTV Video Music Awards party in August (15) and wasn't shy about approaching her about the possibility of duetting on a song.

"I just went up to her and started talking to her," he previously told the magazine. "I was very floored by how well she handled herself and how mature she was. It's nice to get to know the actual person and finding out she's an interesting person ... I'm happy that we're friends."

Meanwhile, Selena said that she also had instant chemistry with Charlie when they first met.

"I just met him a few months ago and we hit it off and we're having so much fun," she told Billboard in December (15). "Charlie pulls out the best in me. It's really great. He's super talented and it (the duet) was fun. It just kind of happened organically, to be honest."

Despite the reports surrounding Selena and Charlie's romance, her ex-boyfriend Justin Bieber is also said to be keen for a reconciliation.

Justin posted a throwback picture of him and Selena kissing earlier this month (Mar16), and just a few days later, Selena was seen in the audience at one of his Los Angeles concerts.

"Justin wants Selena back," a Bieber source told Us Weekly. "He'd love to be with her, but she won't go for it."