Selena Gomez is rumored to be so into new flame Niall Horan it could finally mean the end to her on-again, off-again dalliances with Justin Bieber.

"Selena can't get enough of Niall," a source told Hollywood Life. "When they're not together, they talk on the phone for hours and text non-stop. She is completely infatuated with him."

The 23-year-old "Come Get It" crooner is reported to love everything about Horan, from the way he kisses her to the way he smells.

"She adores his accent," the source said.

"Just hearing his voice makes her totally light up. She hasn't felt this way for someone other than Justin for a long, long time, so it's all really exciting and fun."

Gomez and Horan have only been dating for a short time, but they don't seem shy about expressing their blossoming feelings for one another. The two were recently spotted making out in the middle of a LA club and soon after that were spied at Santa Monica Pier holding hands.

Meanwhile, Bieber is reported to be none too pleased with all the recent developments.

"Justin is absolutely floored that Selena and Niall were seen kissing each other," a source said.

"He and Selena didn't have a commitment to one another, but it still shocked him to learn she got close to another guy in such a public setting in front of everyone."

Prior to that, Gomez and Bieber were rumored to back in each other's arms after recently been seeing on a romantic dinner date where he serenaded her. Before that, the two had openly expressed their undying love and support for one another.

"I'm never going to stop loving her," Bieber said.

"I'm never going to stop checking in on her. We always respected each other and we still respect each other. ... I think we both gotta do some soul searching ourselves, and figure out ourselves before we can just try to figure out each other."