Taylor Swift's "I Knew You Were Trouble" -- Who's It About?

The 22-year-old singer released "I Knew You Were Trouble" at midnight and the Internet is already trying to figure out which of her exes the song is about.

"It's a song that's one of my favorite songs on the album because it sounds just as chaotic as the feeling was when I wrote it," Taylor told ABC News about the sure-to-be-hit. "It's a song about kind of being frustrated with yourself because you have your heart broken and you knew when you first saw that person you saw all these red flags and you just went for it anyway."

So ... what are fans saying online?

"'I Knew You Were Trouble' is obviously about John Mayer," wrote one T-Swift fan. "I knew it before I even heard the song."

"What I learned from Dear John and I Knew You Were Trouble is to stay away from John Mayer," wrote another.

But not everyone thinks it's Mayer.

"Haha omigosh I Knew You Were Trouble probably about Jake Gyllenhaal.... Flying her everywhere," posted one fan referencing the lyrics of the song.

What do you think? Sound off in the comments below!

Lyrics:

Once upon a time a few mistakes ago
I was in your sights you got me alone
You found me you found me, you found me
I guess you didn't care, and I guess I liked that
And when I fell hard you took a step back
Without me without me, without me
And he's long gone when he's next to me
And I realize the blame is on me

Cause I knew you were trouble when you walked in
So shame on me now
Flew me to places I've never been
Till you put me down oh
I knew you were trouble when you walked in
So shame on me now
Flew me to places I've never been
Now I'm lying on the cold hard ground
oh oh trouble trouble trouble
oh oh trouble trouble trouble

No apologies, he'll never see you cry
Pretend he doesn't know, that he's the reason why
You're drowning, you're drowning, you're drowning
Heard you moved on, from whispers on the street
A new notch in your belt is all i'll ever be
And now I see, now I see, now I see
He was long gone when he met me
And I realize the joke is on me

Cause I knew you were trouble when you walked in
So shame on me now
Flew me to places I've never been
Till you put me down oh
I knew you were trouble when you walked in
So shame on me now
Flew me to places I've never been
Now I'm lying on the cold hard ground
oh oh trouble trouble trouble
oh oh trouble trouble trouble