Jayni and Chevy Chase meet a wallaby, courtesy of National Wildlife Federation naturalist Dave Mizejewski. (Leslie E. Kossoff )

“I thank Robert Redford,” he told the audience, and then, looking up, deadpanned, “Where is he?”

Nervous laughter. The superstar had slipped out of the Hyatt Regency Capitol Hill ballroom before the main course, just after accepting the Conservationist of the Year award. (Hey, busy week, promoting “The Conspirator.”)

So Chase rolled with it. “I thank Hopalong Cassidy.” (Get it? Neither Butch Cassidy nor the Sundance Kid.) “I’m just kidding because I know Bob’s not here. . . I just want to know what the river ran through.”

The standard thing at so many of these fundraising galas around town is to give an award to a celebrity for their good works. The NWF changed it up a bit by giving an award to a celebrity spouse: Jayni Chase, a supporter of numerous environmental groups, for promoting energy-efficient schools and educating students. “We try to get into schools,” she said, “because it’s easier than getting into homes!”

The comedian, tasked with presenting the award to his wife of nearly 30 years, enumerated her earth-friendly virtues. “If I blow my nose [into a Kleenex], she says, ‘Did you have to?’ ”

Oh, and “she’s such a good shot.” Haha, like she’s a hunter? Just a joke, folks.

But seriously now: “Jayni asked if I’d play, ‘When I Fall in Love’ on the piano. I’m just going to play it briefly — are you all right with that?”

And so he did. And not badly! But you've seen “Caddyshack,” so you’re not surprised.

Video: Chevy Chase love scene in “Caddyshack”