Taylor Swift and Selena Gomez have reportedly grown apart after the former Disney star reunited with Justin Bieber.

According to a report in Hollywood Life, the 24-year-old Red singer and Gomez's "friendship has been strained."

"Despite Justin's flirtations with other girls, Selena still feels like Justin is a true friend than almost anyone else she knows. She feels like most of her celebrity friends are not legitimate. Justin makes her feel important," a source told the website.

"Taylor is off and on and in her own world. She's friendly with Selena when it's convenient for her. They rarely see each other. Plus, every five minutes, Taylor ends up getting upset with Selena over Justin. They are more like acquaintances with similar interests than besties," the insider added.

However, Swift had previously talked about Gomez during in an interview with E! News when she was at her Keds event at The Americana at Brand event on 9 May.

"It's been the longest one I think either of us had really," she said. "When your life changes and you become thrust into this really strange whirlwind where what your life is different from what other people think your life is. And your life is commented on and your life is written about and fictionalised and all that. Both of us have kind of stuck it out and hung in there through all the different changes we've gone through."

"Longevity is something you really can find very precious and rare in friendships," Swift added.

After multiple break-ups, the 21-year-old Come And Get It singer and Bieber have decided to make things work out.

On 21 September, the couple were spotted together attending a service at Hillsong Church, in Los Angeles, California.

Bieber "uses her faith. That's why they always go to Bible study together, because he knows that when he asks for her forgiveness and tells her he wants to do right by her and by God that it works," another source previously told Hollywood Life.