For Adam Sandler, “Leo,” his animated musical now streaming on Netflix, has been a lengthy labor of love.

Sandler, who produced, co-wrote and stars as the voice of Leo,  first began toying with the idea in 2016 before teaming up with a trio of comrades who directed: Robert Marianetti, Robert Smigel and David Wachtenheim.

Leo is the 74-year-old lizard of the title. He’s spent his life with Squirtle the turtle in a grade school’s classroom terrarium. The two share barbed, funny comments on the kids passing before them.

They’ve been around long enough to know that a motor mouth girl is “an only child” or the quiet one has “divorced parents.” When a substitute teacher (Cecily Strong of “Schmigadoon!”) orders that Leo stay in a different kid’s house each night, one surprise is he can talk to the student. Another is he gives good advice.

“We were all,” Sandler said in a Zoom virtual press conference, “just so excited to actually address that stuff kids go through when they’re growing up. The painful moments, parents’ mistakes. Leo becomes an outlet for kids, someone that they can actually talk to and say what’s going on.

“We knew,” he added, “that was real and we wanted to be thoughtful about that.  But we are all people who believe in comedy and getting as funny as you can. When we slide that stuff in there, we don’t want to overstate anything.  We just like to hit, run, and get to the next piece that hopefully can make you laugh.”

Added Smigel, “Leo’s seen everything. When he connects with kids — that’s the point of the movie! It’s about trust and how we need each other.

“The kids find someone they trust and Leo learns the value of mentoring and teaching as well.”

For Sandler, it’s quite personal. “I look back at elementary school as my favorite time of life. So I was excited to talk about school and friends and feelings you have then.

“I mean, this movie is one of my favorite things in my entire career. I just connect with going to school, being friends and then hear, ‘I’m nervous’ or ‘I’m scared’ and have someone say, ‘You’re not alone. Relax.”

Was there a Leo in his life?

“My family but outside of them — I thought of this today — when I first did standup, me and Chris Rock would talk to a guy there, Lucien Hold, a manager of the Comic Strip. We’d talk to Lucien for two, three hours after a night of comedy. He made us think about how we were progressing, talking about what he thought was cool.”

“Leo” is now streaming on Netflix