Selena Gomez is still torn up about her ex, Justin Bieber -- or she's a really good actress ... that's the only explanation for her sappy and tear-filled performance last night in Brooklyn, TMZ.com writes.

Selena started sobbing and weeping near the end of her ballad, "Love Will Remember" -- which is widely believed to be about her ex-boyfriend, partially because the original leaked version of the song featured a voicemail Justin left for Selena, TMZ.com also writes.

Selena Gomez fell off stage while she was performing her "Slow Down" track in Virginia last week, bringing more attention to a song many believed was dedicated to ex-boyfriend Justin Bieber.

But her public stumble isn't the onlt things fans are dishing out about.

Selena Gomez and Justin Bieber have captured the attention of fans around the world for their on-off relationship, but the teen heartthrob's new "All That Matters" track might discuss his "gut-wrenching" relationship.

"The lyrics of this song are pretty self explanatory - when you fall in love with someone, that someone can make you feel whole. I feel like anyone who has been in love knows what I mean. The song conveys that being in love is one of the greatest feelings on earth. Love is all that matters," Justin Bieber wrote in his website discussing his new song.

"But the void you feel when that love goes away is gut-wrenching. I worked so hard on this song in the studio - trying to put that feeling into music was extremely important to me. I'm happy to share it with you."

Justin Bieber also released his "Heartbreaker" track on Oct. 7 as part of his Music Monday 10-week release, and the hit single's lyrics might be about his ex-girlfriend Selena Gomez. 

When Justin Bieber released the song, he tweeted about the real-life "heartbreak" that he's still going through, HollywoodLife.com reports.