Taylor Swift wants Selena Gomez's ''blessing'' to work with Justin Bieber.

The 'Shake It Off' hitmaker and the 'Boyfriend' singer are reportedly desperate to collaborate in the studio but the 25-year-old star is keen on getting the permission of her best pal - who dated Justin for four years - before doing so.

A source said: ''First of all, Taylor would never go behind Selena's back and work with Justin without first getting her blessing. If Taylor ever collaborated with Justin, it would have to be under extraordinary conditions.

''Justin would like to be free of any beefs with people. It would be one less thing to worry about.''

Meanwhile, the 'Heart Wants What It Wants' hitmaker is said to have been taking musical inspiration from her close friend Taylor.

A source told HollywoodLife.com: ''Selena's written a lot more songs based on her personal experiences and heartbreaks.

''It was Taylor that she drew inspiration from in that sense, who told her that's something she should really focus on because it's what people, especially young female fans, can relate to.

''Selena has written about elements of her relationship with Justin on the new album. She's also taken inspiration from stories of her girlfriends' break-ups and heartbreaks, as she aims to make her music more real than it's ever been.''