Leslie Mann flew in from Los Angeles the other day to promote her new film, “Funny People,” on the “Late Show with David Letterman.” In-flight, the actress and her husband, Judd Apatow, the movie’s writer and director, began to fine tune some anecdotes for her. In the bar at the Four Seasons Hotel, soon after she landed, Mann explained that Apatow, who used to help write “Letterman” bits for stars such as Jim Carrey, “has trained me to be ultra-prepared, to have five stories ready to go. He gives what I say a beginning, a middle, and an end. Whereas I’d just barf it out.” She laughed, an intimate cackle that drew amused glances from the nearby booths. “It’s really lazy of me to depend on him to make me sound sensible, but so what? I’m lazy.”

Leslie Mann Illustration by Tom Bachtell

Turning to the menu, Mann said, “So you’ll have the blueberry-lavender mojito?” She was wearing a gray cardigan, a complicated white T-shirt, very short jean shorts, and gold sandals.

So far, Mann continued, she and Apatow had three stories roughed out. “First off, we got to go to the Oscars this year, and we sat behind Jennifer Aniston, and there was a lot of standing up and clapping, so I was really able to check her out. You know how she looks so perfect in all the magazines, which kind of makes me feel bad about myself? I thought she must be airbrushed, but I was staring at her ass the whole time: perfect. The perfect, perky ass.” She shaped it in the air. “Hair: not a single split end. Skin: tan and glowing, not wrinkly. The lesson seems to be, Go in the sun as much as I want, party more, leave my husband, and have lots of boyfriends. Judd was checking out John Mayer’s ass, too, by the way. Also great.”

The second tale was about “how these mothers of my daughters’ friends ask me about pot. Because Judd makes movies where people are always smoking weed, they think that I’ll know where to get some. Do I look like a pot smoker? I do? That’s awesome! But I don’t do it. I mean, I smoked it in high school, but I didn’t like it. All these comedians who hang around Judd, the boys, like Seth and Jonah”—Seth Rogen and Jonah Hill co-star in “Funny People,” as they did in Apatow’s “Knocked Up”—“used to talk only about pot and porn, but they’re outgrowing their dirty ways. Now they talk about duvet covers.”

That one wanders a little, doesn’t it?

“Yeah, I lost my focus. Probably all the pot I just smoked up in the room.”

There was another yarn, about working with Eric Bana, who plays her husband in the film, and how he has big muscles—but Mann got bored halfway through recounting it, and the conversation moved on to other topics, such as Brad Grey, the C.E.O. of Paramount Pictures. “Brad Grey is handsome,” she declared. “Like, he knows how to give you that look.” She narrowed her eyes and smoldered.

Did he maybe practice that?

“That’s what it is! Yes! Now I don’t find him handsome anymore, at all. Oooh, that’s gross—thank you! Thank you for ruining him for me.”

Mann went on to say that she doesn’t think of herself as a comic actress. “If anything, I take things too seriously,” she said. At one point in “Funny People,” she slips into a deep, mannered voice that, she explained, was “my impression of Nicole Kidman in ‘The Hours.’ I just try to be a dramatic actress, and it comes out wrong, which seems to be funny.” The scorn that Mann’s characters radiate nearly masks their heartache at being neglected. “I’m not really interested in doing a traditional romantic comedy where everything ties up neatly. If I tried to do those roles that Jennifer Aniston is so good at, which are from here”—she indicated her head—“not from here”—she framed her gut—“I would ruin them.”

What would she have to do to get cast in those roles?

“Take a Xanax,” she said, cackling. But didn’t she recently star with Matthew Perry in the breezy “17 Again”?

“ ‘17 Again’ was playing on our flight,” she said. “I looked around, and no one was watching it. I was like, ‘C’mon people, what’s wrong with you!’ ” After a moment—not a scripted Aniston beat but a sneaky Mann pause—she added, “I didn’t watch it, either.” ♦