The pair - who look curiously similar in a promotional shot together - have teamed up for Humperdinck's album of duets which will come out in March.
The duo with a combined age of 141, both famed for many years as lotharios, have recorded a version of the song Spinning Wheel, known for its "what goes up, must come down" lyric.
The album - Engelbert Calling - sees him performing with a succession of familiar names including Smokey Robinson, Willie Nelson, Charles Aznavour, Sir Elton John and Sir Cliff Richard.
Simmons, 64, said of his collaborator: "The Hump rocks. Wanna see how it's done? Let Engelbert Humperdinck show you."
Humperdinck - who is known for hits such as The Last Waltz - was inspired to make the album after he heard a quote from Sir Elton John recalling the days as a struggling songwriter saying "you would sit in your flat waiting for the phone to ring - waiting for Engelbert Humperdinck to call", so he did just that.
He said of working with Simmons: "I had an absolute blast recording and measuring tongue sizes with Gene Simmons. He won - just. It's been a labour of love and I'm truly proud of how it's turned out."
Humperdinck, who famously finished last as the UK entrant at Eurovision in 2012, has also performed with Kenny Rogers, Neil Sedaka, Ron Sexsmith and Andrea Corr among others for his album, which comes out on March 17.