Selena Gomez's friends are concerned about her health and her possible return to rehab, PerezHilton.com reports, leaving many fans wondering if Taylor Swift may be one of them and would consider writing a song about her struggle.

Justin Bieber has allegedly banned Selena Gomez from his upcoming 20th birthday celebrations because she went on a date with One Direction's Niall Horan, Metro UK reports.

Taylor Swift, Selena Gomez's best friend, set her up with the British pop singer.

"Justin is planning a huge party for his 20th birthday and he has not invited Selena,'" a source said, according to the site.

"He does not want her there after she dissed him by hooking up with Niall, which was not cool according to Justin."

Taylor Swift was spotted hanging out with Lorde earlier this week, at the beach and shopping at the mall.

Taylor Swift's "Red" songs and lyrics were written after losing her virginity to Jake Gyllenhaal and their subsequent break up, a source told Radar Online.

"Her breakup with Jake inspired every word of RED."

"The song that specifically references this 'event' is 'The Moment I Knew.' They lyrics are all about her birthday party and Jake not showing up. (sic)"

Taylor Swift and Demi Lovato are siding with Selena Gomez in reportedly trying to take down Miley Cyrus for allegedly hooking up with Justin Bieber, leaving many fans wondering if the "Red" singer will write new song lyrics about the scenario.

"Both Taylor and Demi know how heartbroken Selena's been, and they hate what Miley did to her," a source close to Selena, Gomez told HollywoodLife.com.

All four girls used to be friendly, but when Selena heard Miley started making moves on Justin, it went downhill."

Taylor Swift is currently in the process of writing and recording her still untitled fifth studio album, Hypable.com reports.