Selena Gomez cried over Justin Bieber at Taylor Swift's birthday party.

A source told Us Weekly magazine: "She shouted, 'No one understands me! My boyfriend doesn't even understand me. [Everyone] just stared [at her]."

Meanwhile, Taylor - who invited pals like Beyonce, Jay Z and Justin Timberlake to the gathering at her Tribeca apartment - is believed to have recently offered her 22-year-old friend some dating advice.

Another source shared: "[Taylor] wants her to at least try taking a year off dating. She thinks she should date herself for a while, take the time to get to know herself and appreciate herself.

"But she's not going to force it, she's trying to lead by example this time, instead of forcing her ideas down Selena's throat, she realises she can be kind of pushy and she's working on that."

Selena - who moved out of her parents' home and into her own property in California - has been urged by Taylor to move to New York because the 'Shake It Off' singer has seen a big change in herself since she moved to the Big Apple.

Selena said previously: "[Taylor] wants to kidnap me. She's been begging me every time we get on the phone, because it's been a really good thing for her.

"You know, we've been friends for seven years and she really feels like she kind of stepped into her own and became a woman there, and she's like, 'Alright, your turn!'"