The 'Release Me' singer will release a new collection of duets in early 2013, 45 years after scoring his first number one single.
"We had a great time singing together," John said. "He is so quick, what I call a 'one-take singer' - 76 years old and still sounding as good as ever."
Speaking about his duets project, Humperdinck said: "This album is a true labour of love.
"We have a few more recordings to go, but what a cast.
"I'm keeping most of it under my hat but was so excited about working with Elton, who I have admired ever since first hearing him, that I just couldn't keep it to myself."
The other collaborations on the LP are yet to be confirmed.
"I'm honoured that he has contributed to this album," he added.
Engelbert Humperdinck performed at this year's Eurovision Song Contest for the United Kingdom, finishing second from last for his song 'Love Will Set You Free'.
Elton John scored a number one album earlier this year in collaboration with electronic group Pnau.