Selena Gomez, Justin Bieber Reunite - Again - At A Friend's Birthday Party

The expression is “I just can’t quit you.” And that it exactly what Selena Gomez and Justin Bieber think about each other, apparently.

The on-again off-again couple’s most recent hookup came when they attended their mutual friend Alfredo Flores’ birthday celebration at Bootsy Bellows in Los Angeles Monday night, where they were caught on camera – of course.

In the video, posted by Bieber’s pal Khalil, the couple was seen together at the party and it looks like Gomez, 21, never left his side.

Flores also posted a blurry picture with Gomez taken during the party. He captioned it: “Blurred night with these 2! Happy Birthday Me!”

E! News reported that a source overheard Bieber, 20, and Gomez telling people they were back together as a couple.

“They were holding hands and showed some other PDA, but no over-the-top making out or kissing,” the website wrote. “They were together the whole night and left together at the end of the party.”

Earlier in the day, they were also reportedly spotted having some fun in Malibu with friends.

According to TMZ, they were seen riding in his Cam Am Sypder 3-wheeler as they cruised along the beach.

Last week, Bieber also posted a snapshot – and quickly deleted – of an intimate hug between the two with the caption, “Our love is unconditional.”

Reps for both artists have declined to comment on their (new?) relationship.

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