Teen pop sensation Justin Bieber seemed to be desperate to win back his ex-girlfriend Selena Gomez after their split last week.

The "Beauty and a Beat" singer has reportedly been calling on-off girlfriend Selena Gomez 100 times a day since the break-up. The 18-year-old 'Baby' hitmaker is apparently keen to win Selena back.

Recent tweets from the couple hinted that their relationship is finally over. Justin tweeted, "u know when i want to tweet something but u have no idea what to type. yeah. that is happening right now. lol. love u. and im done. :)"

While Selena posted a photo of herself with a tree adding "thanks for listening, bet you understand".

According to a source quoted by Hollywood Life, "Justin is devastated and pathetic right now. He is calling her 100 times a day and she is not picking up. Selena and Justin flew to Mexico for New Year's Eve, but had a blow-out argument on December 30 and broke up. Selena left Mexico that same day and Justin left for LA on December 31. They have not seen each other since," a source said.

Previous reports claimed the Jelena couple mutually decided to part amicably since things are not working between them.

"Justin and Selena were together for a long time. They love each other and will always care about each other, but it just isn't working between them," a source said.

"So they ended it. Selena is Justin's first love and he is still young enough that he desperately tries to make it work. But Selena is mature enough to just know when to end it and be realistic that it isn't working," the source quickly added.

Justin Bieber was caught in another scandal after photos emerged online which show Justin allegedly smoking pot. However, representatives of the singer repeatedly denied the rumours.

It is reported that the young couple has rekindled their love during their romantic getaway in Mexico last New Year's Eve. It seemed that the two also hammered the details of their renewed relationship. However, this could be a thing in the past.

The Hollywood cute couple is in an on and off relationship after they broke up several times because of various reasons.