Taylor Swift's song The Last Time is allegedly about her ex-boyfriend Jake Gyllenhaal.
The We Are Never Ever Getting Back Together singer - whose new album Red sold 1.2 million copies last week - has revealed the break-up song is about an "unreliable guy" and refers to a Hollywood lifestyle, sparking rumours it is about the 31-year-old Love And Other Drugs actor.
The 22-year-old singer, who dated Jake for a few months last year - told Guy Raz on National Public Radio: "The idea was based on this experience I had with someone who was kind of this unreliable guy.
"You never know when he's going to leave, you never know when he's going to come back, but he always does come back.
"It's a really fragile emotion you're dealing with when you want to love someone, but you don't know if it's smart to."
Last year it was reported that Jake both initiated their relationship and decided to end it because he couldn't stand the attention, leaving Taylor devastated.
"He said he wasn't feeling it anymore and was uncomfortable with all the attention they got," a source said at the time.
"He also said he could feel the age difference.
"Taylor is really upset. We told her not to move so fast with this but she didn't listen."
Taylor recently admitted she has stopped worrying about whether her songs are too personal.
She said: "If I let my fans into my life and my feelings, it turns out they have all those things, too, and it kind of connects us."