'Mine' songstress Taylor Swift was pleasantly surprised when she logged into her official Twitter page earlier today (December 18) as a fellow pop star had praised her latest single.

'I Knew You Were Trouble' has been a popular song for Swift and British superstar Lily Cooper (née Allen) revealed that she's also a fan after writing about her admiration for the track on the social networking site.

She explained: "This Taylor Swift Trouble jam is siiiiiiiccck."

After Swift noticed the message, she replied publicly and thanked her for the support: "Hiiii @lilyrosecooper--thanks! That just made my day:) Merry Christmas!"

Swift recently confessed that she penned the single about a real-life experience that caused her to lose sight of who she really was: "My favourite thing [about the video] is that this girl not only gets sucked into this relationship with him but she loses who she was before and that's the saddest part of losing him, is that she can't remember who she was before she met him." 

Watch Swift perform acoustic versions of three tracks from her latest album, 'Red', below: