The source is not authorized to discuss the split with the press and spoke on condition of anonymity. According to E! News, the breakup apparently happened last week. Distance and their busy schedules were cited as factors.
Eighteen-year-old Bieber is touring to promote his latest album, "Believe," which contains the hit "Boyfriend." Twenty-year-old Gomez is filming a "Wizards of Waverly Place" reunion for the Disney Channel.
Video: Justin & Selena share a kiss at the 2011 Billboard Music Awards
The pair made their relationship public in February 2011 when they attended the Vanity Fair Oscar party together and shared their first public kiss at the 2011 Billboard Music Awards.
Bieber seems to be doing OK, at least publicly. On the red carpet of Wednesday's Victoria's Secret fashion show he said, "I'd rather be here than anywhere in the world."