Justin Bieber and Selena Gomez have called it quits.

According to E! Online, the couple split "about a week ago," due to their busy schedules.

"It was getting harder and harder to maintain a relationship," a source told the site.

Photos of the once happy couple.

Bieber, 18, and Gomez, 20, went public with their relationship in 2011 when they attended the Vanity Fair Oscar party together and shared several high-profile moments, including a [article id="1669835"]red-carpet kiss at the 2011 MTV Video Music Awards and a much-publicized date at Staples Center in Los Angeles, where Bieber rented out the venue[/article] and treated Gomez to a private screening of her favorite film, "Titanic."

Of course, the relationship between Gomez and Bieber's rabid fanbase was never quite as sunny. They frequently harassed her on Twitter and Facebook, and Gomez told New York radio station Z100 that those attacks "hurt ... a lot."

"It hurts, it really does," she said. "I don't feel like I'm doing anything wrong. I've been best friends with him for a very long time. It does hurt my feelings a lot, but I try not to focus on it."

Rumors that the couple had split began circulating over the past few weeks, when Bieber was spotted at a performance of "The Lion King" with a group that included 19-year-old Victoria's Secret model Barbara Palvin.

So far, neither Bieber or Gomez have made any public comment on the rumored split, and MTV News' emails to their reps were not responded to by press time.

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