Are Taylor Swift and Justin Bieber ready to put their rumoured bad blood behind them?The two pop stars reportedly clashed when Bieber was dating founding member of Swift's squad Selena Gomez. But maybe all that's about to change.Bieber extended an olive branch of sorts by posting a video to Instagram that shows him not only listening to Swift's 2007 country hit "Teardrops on My Guitar," but singing along, too. Is it possible he's a secret Swifty fan? Or does country music just gel with this emotional phase he's going through?