"Justin pursued Selena and she gave in," source close to Gomez, 20, explains of the pair, who called it quits after two years in December, just before New Year's Eve. (Gomez and the "Beauty and the Beat" singer, had a "huge fight" during a trip to Puerto Vallarta, a source told Us at the time.)

"They have a crazy connection," a Bieber pal adds, but clarifies: "They aren't back together."

Another insider explains that the hot-and-cold game is par for the course for the young pair. "Who knows with them? They're always back and forth!"