Bill Murray isn’t allowed to spill a very big secret: he’s joining the Marvel Cinematic Universe.

On Thursday night, the actor appeared on “Jimmy Kimmel Live!”, and the host asked him about a recent interview in which he hinted that he would be starring in “Ant-Man and the Wasp: Quantumania”.

“I’m not supposed to say… They’re making a movie,” Murray said of the rumours he started. “Paul Rudd plays Ant-Man. Evangeline Lilly plays The Wasp, and Michael Douglas, I forget what his name is in the movie, and Michelle Pfeiffer, they’re all in the movie. But I’m not at liberty to talk about it.”

According to a report in Variety earlier this week, the “Groundhog Day” star was being interviewed by a German publication when he replied to a question about working repeatedly with familiar directors such as Sofia Coppola and Wes Anderson.

“You know, recently I made a Marvel movie,” Murray responded, immediately recognizing he said more than he should have.

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“I probably won’t tell you, but never mind,” he added, with sleuths figuring out he was likely talking about the upcoming “Ant-Man” sequel, “Ant-Man and the Wasp: Quantumania”.

With the cat apparently out of the bag, Murray continued.

“In any case, some people were quite surprised why I decided on such a project,” said Murray, with Variety pointing out that his comments have been translated from German via Google.

“But for me the thing was quite clear: I got to know the director — and really liked him very much. He was funny, humble, everything you want from a director.”

As Variety notes, Murray didn’t identify the director by name, but did mention “the cheerleader story, ‘Bring It On’” — which was directed by Peyton Reed, who’s also directing the new “Ant-Man” sequel — as a “damn good” movie, part of what influenced his decision.

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“So I agreed, although I’m not interested in these huge comic book adaptations as an actor otherwise,” Murray added.

Judging by Murray’s explanation, it doesn’t seem likely that Murray will be a long-term fixture in the MCU.

“Let’s put it this way: the director is a good guy, and now I’ve at least tried out what it’s like to shoot a Marvel movie,” Murray said. “But I don’t think I need that experience a second time.”