Billie Joe Armstrong thinks it was an "honour" to work with Morrissey.
The Green Day frontman has teamed up with the 'Last of the Famous International Playboys' hitmaker to record a version of The Fifth Dimension's 'Wedding Bell Blues' for the former Smiths singer's upcoming covers album 'California Son' and he's thanked his collaborator for inviting him to be on the single.
He wrote on Instagram: "Hey y'all!! I had the honor of sharing a microphone with Morrissey on a song! Unreal! Thank you Morrissey ! You are truly a legend (sic)"
'California Son' will be released in May and the tracklisting for the record was revealed in February.
As well as Billie Joe's song with Morrissey, Bob Dylan's 'Only a Pawn In Their Game' will be performed by the former Smiths frontman and Petra Haden.
Petra will also appear on a cover of Carly Simon's 'When You Close Your Eyes', with Sameer Ganhia of Young The Giant joining in on 'Days of Decision' by Phil Ochs, and LP - whose real name is Laura Pergolizzi - taking on Roy Orbison's 'It's Over'.
In a statement, LP said: "[I have] great respect and appreciation [for Morrissey]. However, I soon realised when I hung out with him and he played me all the songs he was putting on this record that behind this was the heart of an audiophile and a deep fan of his own musical heroes. He is well versed in so many genres and knows deep cuts of artists I thought I knew so much about. It is inspiring to see the enthusiasm and intellect he brings to people through his own musical journey."
Also joining in the collaborative effort is Ed Droste of Grizzly Bear, who performs Jobriath's 'Morning Starship' with Morrissey, and Ariel Engle of Broken Social Scene, who joins in with Joni Mitchell's 'Don't Interrupt The Sorrow'.