Taylor Swift was hospitalised when an ex-boyfriend crashed a snowmobile they were riding on.
The Love Story hitmaker was travelling on a snow vehicle with a former lover when he lost control and wrecked it, and the pair was admitted to hospital for minor injuries.
Swift has penned a song called Out of the Woods about the relationship and references the incident in the lyrics, writing, "Remember when you hit the brakes too soon/Twenty stitches in a hospital room."
Swift was surprised the accident remained a secret, telling Rolling Stone magazine, "You know what I've found works even better than an NDA (non-disclosure agreement)? Looking someone in the eye and saying, 'Please don't tell anyone about this.'
"People think they know the whole narrative of my life... I think maybe that line is there to remind people that there are really big things they don't know about."
Although the pop star does not mention the boyfriend by name, the interview has sparked speculation that the song is about One Direction star Harry Styles, who Swift dated last year (13).