Selena Gomez and Justin Bieber are back together again but not for a romantic relationship. The former lovers recently surprised their fans with a collaborative song which they titled 'Strong'.

The 'Good For You' and 'What Do You Mean' singers rendered a surprise duet last Saturday which made the fans of the two stars hope that they are really getting back together. Contrary to what many are expecting, the lyrics of their collaborative track talk about the issues they had in their past relationship together.

While the duet of Selena Gomez and ex-boyfriend Justin Bieber seem to indicate that they are in good terms, a source reveals that the track is no longer new. Gomez and Bieber's new song 'Strong' is said to have been recorded three years ago for the sake of fun.

According to ET, the former couple never intended to release their song. Many are thinking that the track might be featured on the upcoming album of Justin Bieber 'Purpose' which will be released this coming November 13 but the source says otherwise. 'Strong' is not going to appear on the 21-year-old's upcoming album nor on Selena's.

The lyrics of Selena and Justin's duet seem to discuss about their complicated relationship. The two have been on-again/off-again when they were still together.

"What should I do? Should I go? / Who do I talk to? Nobody knows," sings Bieber in the track to which Gomez replied "Wishing I was better at this damn thing / 'Cause it's just been too long and I can't change."

Neither of the Hollywood stars publicly mentioned about the said track. Selena Gomez and Justin Bieber have not yet commented on the song.

Meanwhile, 'The Heart Wants What It Wants' singer has once again topped the Billboard with her 'Revival' album which sold 117,000 copies sold during its debut week. The 23-year-old 'Come and Get It' singer maintains to be on the Hot 100 with her 'Good For You' single starting from June.