I've seen a few version of this around but none of them seem entirely correct.  So here's my shot at it.


Intro:  Synth prelude then beat intro
 
G      C      C      D  D7      (X2)

Verse 1:
G           C     C                  D D7
Once upon a time, once when you were mine,
G          C      C                 D D7
I remember skies, reflected in your eyes.
  F                C       F             C
I wonder where you are. I wonder if you think about me.
G           C            D  D7   G        C      C     D  D7   
Once upon a time in your wildest dreams.  


Verse 2:
G                  C        C               D       D7
Once the world was new. Our bodies felt the morning dew that
G                  C     C                   D      D7
greets a brand new day. We couldn't tear ourselves away.
  F             C        F             C
I wonder if you care.  I wonder if you still remember.
G           C            D  D7   G           C     G (shortened)
Once upon a time in your wildest dreams.


Chorus:
G              C          C                  D7
When the music plays, and when the words are touched with sorrow.
G              C        C                D7
When the music plays, I hear the sound I had to follow, 
G           D7
Once upon a time…


Verse 3:
G                C           C            D  D7
Once beneath the stars, the universe was ours.
G               C         C              D  D7
Love was all we knew, and all I knew was you.
  F             C       F             C
I wonder if you know, I wonder if you think about it.
G           C            D  D7   G         C       C     D  D7
Once upon a time in your wildest dreams.   Ah.....





Verse 4:
G           C           C          D  D7
Ahhh…
G           C           C          D  D7
Ahhh…
F           C           F          C             
Ahhh…
G           C           D7         G  C      G
Ahhh…


Chorus:
G              C          C                  D7
When the music plays, and when the words are touched with sorrow.
G              C          C                  D7
When the music plays…
G              C        C                D7
When the music plays, I hear the sound I had to follow, 
G           D7
Once upon a time…


Verse 5:
G           C     C                  D  D7
Once upon a time, once when you were mine,
G          C      C                D  D7
I remember skies, mirrored in your eyes.
  F                C       F             C
I wonder where you are. I wonder if you think about me.
G           C            D  D7   G 
Once upon a time in your wildest dreams.
G           C            D  D7   G 
(Ahhh…)          in your wildest dreams.
G           C            D  D7   G 
(Ahhh…)          in your wildest dreams.
G           C            D  D7   G 
(Ahhh…)          in your wildest dreams.
G           C            D  D7   G        (Repeat to end)