Justin Bieber and Taylor Swift have written a song together.

The 'Baby' hitmaker - who is currently dating the 'Love Story' singer's close friend Selena Gomez - have penned a track together in the studio, according to Grammy award-winning songwriter and producer Kuk Harrell, who has worked Rihanna and Katy Perry in the past.

He wrote on twitter: "Wow!! Got to see @justinbieber & @taylorswift13 write a song together last night!! SMASH!!!! SMASH!!! SMASH!!! Let's do it again Yall!!! (sic)"

He then tweeted the 21-year-old beauty to praise her and the 17-year-old pop sensation for their work.

Kuk wrote: "@taylorswift13 You and Justin Killed that writing last night!!! SMASH!!!!!!!"

Justin and Taylor's collaboration comes shortly after the 'Never Say Never' singer made a surprise appearance on stage with the blonde stunner to perform his song 'Baby' with her as part of her 'Speak Now' tour gig at the Los Angeles' Staples Center on Tuesday (23.08.11).

Following the concert, Taylor tweeted: "You think you've heard LOUD screaming in your life. Then @justinbieber comes out and does a surprise song during your show. Woah. Unreal. (sic)"


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