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The rumor mill doesn't need much prodding to link a couple of famous faces together: Proximity, opposable thumbs and a pulse are typically all that's required. With that in mind, Selena Gomez has been romantically linked to a newly single Niall Horan after the two posed for a photo with some fans while out together in London over the weekend.

The fans called the meet-and-greet "so nice" and tweeted the pics, although the one who posed between the boy-bander, 20, and the fresh-out-of-rehab starlet, 21, was shy enough (or smart enough, given how rabid some 1D enthusiasts can be) to Photoshop a cat head over her face.

It remains to be seen if Selena's rendezvous with Niall was merely a meeting between pals or a sign of a burgeoning romance. The pair were last seen together onstage at the MTV Video Music Awards last August, when One Direction presented Gomez with the Best Pop Video prize for "Come and Get It."

Selena spent part of January in rehab, a decision that came a few weeks after she canceled her Australian tour and told fans she planned to "spend some time on myself in order to be the best person I can be."

Sources claim her treatment was due in part to her dysfunctional, on-off romance with Justin Bieber.

"Selena came to understand just what a bad influence Justin had been on her life," an insider alleged to Radar Online. "Their relationship left her broken-hearted."

Horan, meanwhile, recently called it quits with model Barbara Palvin.

"There was no big fall out," a source explained to the Sun. "Things just fizzled out as Barbara and Niall are both working in different parts of the world."


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