Piggie (Lauren Williams, left) and Gerald (Evan Casey) attempt to dress appropriately for a pool/costume party. (Teresa Wood)

It takes a lot to dazzle my 5-year-old son. He wasn’t impressed when his mom talked to “the man who pretends to be Captain America.” Same when I met “the man who is Woody’s voice.” But when I told him I was interviewing “the man who wrote the Piggie and Gerald books,” there was a gasp.

That’s because Mo Willems creates books that kids adore and parents enjoy even after 34,931 readings. He’s also behind the Pigeon franchise, in which a pigeon expresses indignation over various scenarios, and the Knuffle Bunny books, which follow a little girl and her stuffed rabbit in the big city.

Willems brought Knuffle Bunny to the Kennedy Center in a 2010 original musical; his second collaboration with the Kennedy Center is “Elephant and Piggie’s We Are in a Play!” a musical featuring Gerald, the elephant, and Piggie, his best friend.

“Every Elephant and Piggie book is really about two friends blowing it, two friends messing up their friendship in some way, and then having to rebuild it and being stronger for it,” Willems says.

It’s the same for the show, which is a vaudeville-style revue of Piggie and Gerald’s greatest hits. “I see this play as a series of existential crises that continue to build,” he says. “But for kiddies!”

The books are intended for early readers; Willems keeps them to fewer than 60 pages and only uses 40 to 50 different words per book. So staging the pink and gray odd couple’s adventures gave Willems, who wrote the script and lyrics for “We Are in a Play!,” a refreshing change.

“To be able to see them and write them for longer periods of time, using longer words, was a real joy,” he says. “I got to use multiple syllables.”

What the change of venue didn’t do, he says, was make the characters any more alive to him (or, he hopes, to his readers). “They are in books,” he says. “There is no medium more alive.”

Angry Bird

The star of the Pigeon series is hidden in most of Mo Willems’ non-Pigeon books. In “We Are in a Play!,” Willems says, “there is a very subtle mention of the pigeon and he’s annoyed. He’s annoyed he’s not in it more.”

Kennedy Center, 2700 F St. NW; through Dec. 31, $29; 202-467-4600. (Foggy Bottom)