The song, which will be released April 8, “highlights another year of inspiration for me, in regards to my music, photography and philanthropy work, and 'Someday' is a reflection of that,” Lennon said in an email announcing its release.
Lennon also said his album, Everything Changes, which has previously been available in the UK, will be available worldwide shortly after the single is released.
Tyler told the London Evening Standard that he and Lennon decided to collaborate after Lennon heard him sing in the shower.
"A lot of stuff happens in L.A. We were staying at a hotel where Julian Lennon was staying, and one morning I was singing in the shower. The window was open, and I just heard, 'Steven?' We brought him over to the studio and he sang on the opening track," he said.
Read more at Examiner.com.