Selena Gomez reportedly threw a fit at Taylor Swift's birthday party, putting a damper on the whole celebration, as she cried over her split with ex Justin Bieber.

According to Us Weekly, Selena Gomez reportedly made a scene at Taylor Swift's birthday party at her apartment in Tribeca on December 13 as others looked awkwardly on.

"She shouted, 'No one understands me! My boyfriend doesn't even understand me," a source told the magazine.

Nobody knew how to react and everybody "just stared" at Justin Bieber's ex.

"While fellow partygoers like Beyonce and Jay Z enjoyed beers, pizza, and sushi and mingled with pals like Justin Timberlake, Gomez, who has dated Bieber on and off for three years now, was reportedly getting emotional over the 'Boyfriend' singer," the magazine added.

Taylor Swift and Selena Gomez are BFFs who reporteldy had a falling out at one point due to her toxic relationship with Justin Bieber. Whenever the two have a fight, Selena Gomez allegedly ran crying to Taylor Swift.

When she could no longer take the aggravation, and seeing what the relationship was doing to her friend, the multi-awarded singer allegedly told Selena Gomez to choose between their friendship and Justin Bieber. The "Come & Get It" singer chose the latter.

"They did not leave it on good terms - it's very icy. They both decided they need space," a source told Hollywood Life back in March. "Things have been going downhill between them for a while. Taylor can be very opinionated and controlling, and that's been getting on Selena's nerves.

Despite Selena Gomez's emotional outburst, the birthday party of Taylor Swift was reportedly a rousing success with everybody in attendance, maybe even including Justin Bieber's ex, having a blast.

"Fortunately the birthday girl did not notice as she was too busy with her high profile guests, who also included Karlie Kloss, Chrissy Teigen, Kelly Osbourne and band Haim that had performed with Taylor earlier at Z100's Jingle Ball," said MailOnline.