The singer, 74, had been hoping to keep their new Christmas duet a secret until it was ready to be released, but Sheeran, 30, recently made the announcement on Dutch radio station NPO Radio 2 without consulting his duet partner.
“Yeah, he let the cat out of the bag, didn’t he?” John told NME when he was asked about the gaffe.
John continued: “I was sworn to secrecy and then big mouth f***ing Sheeran goes to the Netherlands! It’s supposed to come out – we haven’t finished it yet, so there’s still work to be done.”
Speaking about his hopes to score the coveted christmas number one spot, John said: “We’ve got the sausage roll man to deal with, haven’t we? We’ve got LadBaby to deal with!”
LadBaby has topped the charts at Christmas for the past three years running.
Sheeran previously said the idea to do a Christmas song came from John, who rang him on Christmas Day 2020.
“He said [his 1973 hit] ‘Step Into Christmas’ is number six on the charts, and I’m 74, and I’m still having f***ing chart hits, this is great!”
There is currently no release date or title for the new song.