And Harris got his wish - the legendary rocker arranged the date straight away, and the actor reveals he was impressed by the pair's parenting skills.
He tells Access Hollywood, "Elton and David came to our house for Zachary's first play date a couple (of) weeks back. They're great guys. They're super great parents. They're so fiercely involved in their son's life and it's really kind of great to watch them interact with him."
Harris and Burtka welcomed their kids by surrogate in October (10).