Taylor Swift's songs are famously autobiographical. Now fans have figured out that her newest one, 'Back to December', is almost certainly about ex-flame, 'Twilight', star Taylor Lautner.

Swift has already confessed the song is "almost word for word" a conversation she had with a heartbroken boyfriend but refused to name him.

The songs includes references to "beautiful times" in the "summer" (the pair filmed 'Valentine's Day' in the summer of 2009) and "laughing from the passenger side" (the paparazzi shot her laughing in Lautner's car). It also includes the line: "I loved you in the fall".

When Swift hosted US TV show 'Saturday Night Live' last November, she sang about Lautner. 

Watch the official video for 'Fifteen' below: