Who is the guitarist of the melodic blues line in “I want you (she's so heavy)” of The Beatles?

Question

Since the beginning of I want you (She's so heavy) of The Beatles, two beautiful guitar lines have been recognized. A baroque circular arpeggio that becomes almost hypnotic, and a blues melody that accompanies (sometimes notes by note) the voice of John Lennon in the strophes. This guitar melody is also performed as a solo, without the singing voice.

I imagine the four Beatles playing this song with their respective instruments (of course I'm wrong, the song is a studio and perfectly John can play all the instruments by himself). There is no doubt about the voice (John), the drums (Ringo) and the bass (a very inspired Paul). The synthesizer, very hippie, by the way, I do not know who interprets it.

My question is about the guitar, because I would like to put a face to each interpreter. Who plays the lead guitar (ie, strophe melody and solo) in this incredible song, George or John?

Answer 1

This transcription of a George Harrison interview in 1969 says that John Lennon played it:

John plays lead guitar and sings the same as he plays. And, uh...this is good because it has, um - it's really basically a bit like a blues. The riff that he sings and plays is really a very basic blues-type thing. But again, it's very original sort of John-type song. _{archive link}

Keyboards are played by Billy Preston.

Preston also worked, in a more limited role, on the Abbey Road album, contributing organ to the tracks "I Want You (She's So Heavy)" and "Something".