As one of our era’s most masterful comedic actresses, Megan Mullally is clearly familiar with the whole celebrity-interview trope. A star wafts into such-and-such swanky restaurant, orders a burger, effuses “realness.” So when Mullally steps into a divey Laurel Canyon bar in Los Angeles clad in a ginormous, tie-dyed T-shirt emblazoned with the Cat in the Hat smoking a spliff, and orders only water, it’s clear what she thinks about Hollywood convention and the myth-making that goes along with it.

She is not all that interested in playing along.

Auburn-haired, with a strict middle part, Mullally, 60, sports outsize professor-ish glasses and a jangle of crystals around her neck. “I am no stranger to a tarot-card reader or a psychic or a crystal,” she laughs. She and Busy Philipps, a kindred spirit, bonded over the crystals’ provenance. The T-shirt is vintage, by the way, and when she discovered it, she thought, “That’s the greatest T-shirt, ever, in the world.” Weird, if you hadn’t guessed, is kind of her thing.

Fashion flair aside, in person, Mullally, who won superfans and Emmy awards as the inimitable and outrageous diva Karen Walker on “Will & Grace,” is self-contained, not desperate to dazzle with one-liners. “I always feel like I’m not ‘on.’ In the moment, I don’t feel like I want to be performing unless I’m getting paid to do it. I get embarrassed. In reality, I am much more of an introvert.”

On Oct. 24, Mullally will take her last bow on the final season of the revival of “Will & Grace,” the show that gave the actress her first major mainstream breakout (at the age of 39) in 1998 and established her as a unique force in arch physical comedy. So seared into the popular imagination is Karen’s shrill voice and flamboyance, she regularly has to remind fans that she and the sitcom diva are polar opposites.

“I’m really so different [from my character]. I don’t drink, and I’m totally straight-laced. Drinking doesn’t agree with me — I’m too small, I can’t sleep. [When I drank] at parties, I always felt like I said something stupid, and I am perfectly capable of saying something stupid when I am sober. I don’t even drink caffeine.”

She is sanguine about closing out an era (all over again). “I was really a cheerleader for the reboot, and it’s been wonderful. I do think it’s time to move on.”

When confronted with the rumors that the show’s end stemmed from a long-simmering feud with her co-star Debra Messing, Mullally laughs. “You mean like Bette Davis and Joan Crawford?”

Fans of the show have scoured Mullally and Messing’s Instagram accounts looking for supposed clues, like a quote on Mullally’s feed saying, “One of the best feelings is finally losing your attachment to somebody who isn’t good for you!” (since deleted). Mullally is sphinx-like about the topic. “I don’t know, I don’t feel anything about it. I can’t be responsible for what people think about my Instagram. It’s weird that people would even notice things, that kind of freaks me out.”

Feud or none, Mullally is deft at creative collaboration. She is especially keyed up about Nancy And Beth (with the “A” inexplicably capitalized), her genre-defying band with performing partner Stephanie Hunt, who is 30 years her junior, a sort of hipster doppelgänger and artistic soulmate.

The pair, who will drop a new album next spring, create original music and choreography for their music videos, often wearing identical clothing, looking rather like “The Shining” twins in a mirrored funhouse.

In one video riff, they perform Gucci Mane’s extremely NSFW song “I Don’t Love Her.” The result is at once totally absurd and totally searing feminist commentary on the rapper’s lyrics. In her typical deadpan style, Mullally has said that Mane appeals to her, because he’s “a man who speaks his truth.”

The daughter of an actor, Mullally was raised between Los Angeles and Oklahoma, eventually studying dance at the School of American Ballet in New York and establishing herself as a theater actress in Chicago. “I sort of came out of the womb in a top hat and tap shoes, I really did. All I wanted to do was dance in my room.” For the band, “I do all the costumes,” says Mullally, who is especially proud of a trippy recent shoot in which she and Hunt don matching Adidas tracksuits. “Stephanie’s kind of like a faerie who is really savvy and smart. So when we get together, it’s like a little girls’ tea party, and we lose all concept of time. That’s why I love it so much; it’s pure. We can do whatever we want. With Nancy And Beth, I get the creative autonomy I’ve never really had.”

Mullally is philosophical about her place under the bright lights of the comedy world. “If I were 15 years younger, or maybe even 12, I would be more in that Tina Fey/Amy Poehler arena, but I am just a little bit older and that more kind of odd, experimental stuff wasn’t really happening when I was starting out.” Finding herself as a successful commercial sitcom actress, Mullally saw she had to create the avant-garde for herself.

With her husband of 16 years, Nick Offerman (of “Parks and Recreation” fame), Mullally has done just that, crafting an offbeat professional partnership that resulted in the 2018 memoir “The Greatest Love Story Ever Told,” which was released in paperback this fall. The two are also about to drop a new podcast in which they riff on their idiosyncratic married life and interview guests like their mutual friend Bill Hader. The effect of these projects is like sitting in the couple’s living room, eavesdropping on the strange corners of their brains — reality show meets performance piece.

Seemingly comfortable with the art of the overshare, Mullally still keeps some cards close to her vest. “The stuff we’ve said [in our book] is all real and true, but what we really have together, no one would really ever know, so it’s this built-in protection where I don’t feel we’ve ever compromised anything. We have secret dogs. We have a celeb dog [Clover, top right], and then we have some dogs you’ll never know about … we do have secrets.”

“Nick and I have been pretty darn lucky in our careers, but at the same time, we’re not Hollywood-y. At all. A paparazzi might take our photo as an afterthought if we are standing behind a Victoria’s Secret model at the airport. Otherwise, they are like, ‘OK, we’ll pass.’ ”

At home, she notes, “I do like making him laugh, so there’s an element of that, but we also spend an inordinate amount of time doing puzzles, listening to an audiobook or the Cubs game. We literally have no social life.”

They obsessively devour books and watch art-house hits like “Bachelor in Paradise” (“my muse,” she jokes). When Mullally doesn’t feel like going out (which is always, she reports), she hosts one of her “Girlfriend Spectaculars,” an all-female gathering at the Bel Air home she shares with Offerman.

“There’s something chemical that happens when you only have women present. It’s all in the casting; I try to invite cool, great women, actors, dancers, writers, people who aren’t in the business.” For dessert, she hires a little ice cream cart; she is contemplating adding live music to the offerings. “I mean, just crazy stuff happens when we get together.”

When asked if she cooks for the occasion, Mullally channels a bit of spoiled Karen Walker and deadpans: “Hell no.”

We’re eagerly awaiting our invite — and a glimpse of the secret dogs.

Editor: Serena French; Stylist: Anahita Moussavian; Hair: John Ruggiero at The Wall Group using Bumble and bumble; Makeup: Dana Delaney at Forward Artists using Cozzette Beauty