I've had a few changes of thought, but this is the new conclusion I came up with. Maybe one of you could so kindly confirm or suppress this:
First, I thought it was John, because on the AYNIL video, you see John singing, which should be proof enough.
Then I realized that Paul was actually movnig his mouth too, which made me think, "Eh? So who's singing this?"
Well, I did some research on the What Goes On website and other places, and have come to this conclusion:
The "Woah yea!" at the end is definitely Paul, during the "Love is all you need" coda.
The SAME voice sings, "Loves You yea yea yea" afterward. Not to mention that John JUST finished singing, "Love is all you need." and wouldn't be able to take a big enough breath to do that.
However, you DO hear John's cracking voice during the second, "She'd love to, yea yea yea" which signals that John joins in, and it becomes Paul and John.
Is this a sound theory? Seems like it makes sense.
Its described pretty well in Mark Lewisohn's Recordin Sessions book. They had recorded it, and when they went to the live feed, George Martin and I think Geoff Emerick were working in tandem with them from a different studio, so there is some crossover. Pulled off brilliantly though, and at that time, it was broadcast to the largest audience ever.
I dunno what's been said in this thread already, but I've listened to AYNIL millions of times and seen the videos thousands of times, and I always thought for sure it was Paul... It sounds just like Paul's voice with his little tones and accents and all that...
However, there is a bit of mystery after carefully listening to the voices in the song near this point at the end...
Here's a little rundown: 1. At approximately 2:30 a voice (Paul's) shouts "all together now" 2. Then (the same voice), "everybody" at 2:35 -In the video, you can cleary see that Paul is saying this... And his distance from the mic was about a foot or so further back than he was for the rest of the song, which resulted in the change in the sound of his voice 3. At 3:06 Paul "yee-hoo"'s 4. This is followed by John's "Ye-hay!" at 3:08 5. Between 3:10 and 3:17 John begins with "y'need", then repeats the chorus again, then ad-libs a bit. After this he continues on with "love is all you need." 6. At 3:21 a voice that sounds identical to the one in 1 and 2 of this rundown shouts "Oh yeah!" 7. At 3:23 the voice continues with "love you yeah yeah yeah" 8. At this exact time, Lennon's voice stops singing the main chorus 9. The first voice continue's with "she love you yeah yeah yeah"
Listening to several bootleg versions didn't help... So I'm still under the influence that it's Paul, because his voice sounds so much like that...
Also, later in the song on bootleg versions (where it doesn't fade out), you can barely hear John saying stuff as the song continues, which don't sound anything like the voice singing "she loves you", etc...
Anyway, if there was a check mark to check when a post a utterly useless, my post would be checked... Sorry all