The song features Rihanna duetting with Chris Martin. The Coldplay frontman admitted to The Sun that it took him a while to finally muster up the nerve to ask the Bajan superstar to contribute some vocals.

Lyrically this song finds Martin writing from a female point of view. He told NME: "I found that with Viva La Vida, I enjoyed writing from someone else's perspective to actually get out what I was feeling. That song is from a girl's perspective. I wonder what that says about me?" "it took so long - there's still this tribalism in music where we're rock and you're hip hop, and sometimes it takes a while to get across those barriers."

Have a look at the BEHIND THE SCENES video to see how it was filmed.

Ohhhhh....

Once upon a time somebody ran
Somebody ran away saying:
"Fast as I can I've got to go"... (I've got to go)

Once upon a time we fell apart
You're holding in your hands
the two halves of my heart
Ohhhhh, ohhhhh!

Ohhhhh....

Once upon a time, we're burning bright
Then all we ever seem to do is fight
On and on...
And on and on and on...

Once upon a time on the same side.
Once upon a time on the same side, in the same game
And why d'you have to go
Have to go and throw it all in my flame

I could've been a princess, you'd be a king
Could've had a castle and worn a ring
But noooooo, you let me gooooooo!

I could've been a princess, you'd be a king
Could've had a castle and worn a ring
But noooooo, you let me gooooooo!

Stole my star
La, la, la, la, la, la, la, la...
You stole my star la, la la la la laaaaaa

Oooooooh-oh oh oooooooh oh oh oh ohhhhhhhhh
Oooooooh-oh oh oooooooh oh oh oh ohhhhhhhhh

Cause you really hurt me
No, you really hurt me
Cause you really hurt me
No, you really hurt me
Cause you really hurt me
Ooooooooh no, you really hurt me
Cause you really hurt me
Ooooooooh you really hurt me....

ONCE UPON A TIME= A long time ago.
This is the usual way to begin stories, especially fairy tales.
UPON= On (old fashioned)

FAST AS I CAN= As fast as I can = very very fast.

FELL APART= If a relationship falls apart, it ends badly (destroyed from the inside). But if a person falls apart, he or she is emotionally or psychologically devastated. When he says “we fell apart” it may mean “we both, our relationship, fell apart” or maybe “you fell apart and I fell apart”, so it is not clear if he’s talking about the end of their love affair or about the emotional consequences for each of them.

HOLDING= If you hold something, you have it in your hand.

HALVES= /hævz/ Plural of “half”. A half is the 1/2 part of something (0.5). Two halves make a whole, a unit (2/2). In standard BrE it is usually pronounced /hɑ:vz/ 

HEART= /hɑ:*t/

WE'RE BURNING BRIGHT= (metaphor) We're having a great relationship.

ALL WE EVER SEEM TO DO IS FIGHT= Apparently, we’re always fighting.

ON AND ON= Non stop, continuously, all the time.
The verbal particle ON expresses continuity.

ON THE SAME SIDE= If two people are on the same side, they are friends, or defend the same idea, or have the same goal, or think in the same way.

D'YOU= /dʒu:/ = did you ( /du: ju:/) assimilation rule number 2
"D'you" is usually the colloquial contraction of "do you", but sometimes it may be "did you", according to the context.

COULD'VE HAD A CASTLE= pronounced here: /kʊdəvədəkæsəl/. It is quite common not to pronounce the H sound in some grammatical words such us: him, her, have, has, had, so instead of "could have had" we hear "could've'ad".
This sentence is just a hidden form of a 3rd conditional type, where the subordinate clause is implied (not mentioned) and the auxiliary WOULD has been replaced by another auxiliary: COULD. The complete form would be:
- if you hadn't let me go, I would have been a princess, you would be a king and I would have had a castle and wear a ring. (but you let me go, so now I'm not a princess, you're not a king and I don't have a castle or wear a ring)
Another example:
- If you had married me when we were 25, I would have been happy
= I could have been happy (if you had married me then) (but you didn't, so I'm not happy)

CASTLE= /kæsəl/  (BrE /kɑ:səl/)

YOU LET ME GO= (let - LET -let) You didn’t do anything to stop me leaving you, you didn't fight for me.

MY STAR= (metaphor) My good luck; my destiny.

CAUSE= (coll.) Because.

HURT= (hurt- hurt- hurt) Cause pain, make suffer (here it is used in the past tense)

There's not much of a meaning to this song. All she says is that we were lovers but one day you ran away from me and I'm hurting so bad. He also thinks he's hurting so bad.

So here they are, two broken-hearted lovers blaming each other for what happened. Same old story.