Sheeran played a surprise support slot at the band's gig in London last week
The musician said he still had to live "with the consequence" of the split
"I think I accidentally ruined our relationship too with a massive faux pas"
Ariana Grande, Lily Allen and Coldplay were amongst a host of artists who made the final rundown
The global popstar also joined them later to perform 'Love Is Only A Feeling'
They led the audience in a rousing rendition of ‘Fairytale of New York’
"I remember when I got to about 18...and thinking, 'Well this is over, I'm already too old!'"
The film is set to be released in cinemas for one night only on November 9
The documentary sees the band attempt to recapture former glories after reuniting in 2011
The shows will see them perform their 2003 debut album in full