The couple, who had been dating since 2010, went to Puerto Vallarta, Mexico, together at the end of December to celebrate the new year, but got into another "huge fight," which prompted Gomez to "abruptly" fly back to Los Angeles solo on Dec. 30, Us Weekly reports.
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They later celebrated New Year's Eve separately — Gomez attended a house party with friends and Bieber went to a club with his BFF, rapper Lil' Twist.
There's no word on how Gomez is handling the breakup, though she tweeted on Jan. 1: "New beginnings. Fresh start. I love you all :)." Bieber, on the other hand, has not had a very good 2013 thus far. Last week, a paparazzo was killed while trying to photograph Bieber's car, and TMZ later posted photos of the teen heartthrob smoking what appeared to be marijuana the day after the incident.