It was a big day for the kids in Mr. Ratburn’s grade-school class — and, by extension, the children (and parents) who watch the long-running PBS Kids series Arthur. In today’s Season 22 premiere of the animated show, Arthur and his friends learn that their teacher Mr. Ratburn was going to be married.

What none of them was expecting is that he is tying the knot with an aardvark named Patrick.

The episode, titled “Mr. Ratburn and the Special Someone,” shows the teacher taking a cell phone call while preparing to hand out a pop quiz on homework. They overhear talk of flower arrangements and get him to admit that he’s headed to the altar. Arthur, Buster, Muffy and Francine then set off to learn the identity of the bride. They casually spy on Mr. Ratburn, intervening when they think he’s marrying a bossy female rat and trying to convince librarian Mrs. Lancaster that their teacher who amorous — if clumsy — love poems to her. No dice.

The scene later shifts to the wedding, where the third-graders are “disguised” as grownups but soon are called out — Buster’s hippie getup ain’t makin’ it — but the kids still don’t know who he is marrying. Speculation spikes when they see that female rat from earlier, who turns out to be his sibling. “If Patty is his sister,” Arthur begins … “then who is Mr. Ratburn marrying?” Muffy finishes.

Cut to the aisle, where Mr. Ratburn is heading for the altar arm-in-arm with his chocolatier soon-to-be-husband. Patrick gives the slack-jawed kids a wink as he passes them and is met with smiles.

Cementing the message of not only tolerance and acceptance, but no-big-dealness, nothing is made of the gender of their teacher’s newly betrothed. The segment ends however, with Francine adsserting, “But there’s one thing teachers should never, ever do.” “What?” Buster asks.

“Dance.”