The 'Ordinary People' hitmaker is to appear in a forthcoming episode of the children's TV show and got the Muppets, including Big Bird and Elmo, to send a message to his and his wife Chrissy Teigen's seven-month-old baby girl.
In a clip posted on John's Instagram account, the Muppets say: "Hello Luna. We love you so much. You are so cute. Kiss, kiss."
The 37-year-old singer hopes that when his little girl is grown up she will appreciate the message from the popular kid's characters.
He captioned the video: "One day Luna will be very excited by who daddy hung out with today. (sic)"
John's 31-year-old model spouse was almost reduced to tears watching her husband recording the sweet message for Luna and she can't wait for her to see it.
Taking to Twitter, Chrissy wrote: "My heart!! I could cry. I cannot wait for the day Luna goes absolutely nuts over this. (sic)"
And the Muppets are not the only ones John is gushing about Luna too, as he recently revealed he bonded with his 'La La Land' co-star Ryan Gosling - who has daughter Esmeralda, two, and Amada, seven months, with partner Eva Mendes - over fatherhood on the set of the eagerly-anticipated movie.
He said: "Amada and Luna were both born in April. We talked about it.
"We had just announced that we were pregnant right around when we were filming the movie, so . he definitely kind of shared how joyous it is to be a new father and gave me something to look forward to."
Meanwhile, John is looking forward to Luna's first Christmas.
He said: "Christmas with Luna is going to be really exciting. It's the first time at our new house, we've never had our own Christmas at home. We usually travel somewhere, go to a family member's house and we go on vacation. This is our first time actually having a tree at home, in our new place. And we have a new baby. It's pretty exciting."