Krysten Ritter just wants to have fun

Behold a scene of lust and betrayal between a young woman and another woman’s fiancé, on top of a kitchen table. Make that on top of a birthday cake. On the betrayed woman’s birthday. Oh, and the women are roommates. Then discover that it’s not only excusable behavior but also actually a kinky act of kindness.

And that’s just the opening scene of “Don’t Trust the B---- in Apartment 23,” ABC’ssubversive midseason addition to the quirky-girl comedy trend, which has its season finale Wednesday. The debaucher on the cake is Chloe, described by creator Nahnatchka Khan as “a woman with the morals of a pirate.” Played with gusto by Krysten Ritter, Chloe cuts a swath of destruction across Manhattan. Into her path trips innocent June (Dreama Walker), fresh off the turnip truck from Indiana. June desperately needs a place to live; Chloe needs a new mark. It’s a match made in comedy heaven.

Audiences may remember Ritter as a b---- of another stripe, in AMC’s “Breaking Bad.” In fact, those who saw her couldn’t forget her. She played Jesse’s girlfriend Jane, whom Bryan Cranston’s character calmly watched die in Season 2.

“She enhanced and obliterated everyone on-screen,” says executive producer David Hemingson of Ritter’s portrayal. She was everyone’s first choice for Chloe. Meanwhile, so many people in Ritter’s life — agent, manager, friends — told her she was perfect for Chloe that she started wondering what they thought of her.

“Everyone was saying, ‘Oh, my God, this character is so you,’” Ritter recalled on the set last fall. “And I’m like, ‘People, am I missing something here? Are you suggesting I’m a b----?’”

Over the years, in a string of indie films and TV shows from “Veronica Mars” to”Gilmore Girls,”the actress has played her share of sassy best friends and dark junkies. Chloe is a winning mix of the two, as Ritter explains: “She’s not a junkie, but she’s a party girl and likes to have a good time. She’s dark, but she’s also fun.”

Although Chloe has done some horrible things this season, Ritter doesn’t see her as a horrible person. Even pirates have a code. “She’s just someone who doesn’t have any attachments,” she says. “That’s how I play her, so that makes her a little light on her feet; it kind of balances out the danger.”

Adds Hemingson, “Chloe’s got this freedom to explore. She’s like Vasco da Gama in Louboutin heels.”

And Ritter is front and center this time, in a lead role instead of another scene stealer. She relishes the chance to play a girl “with absolutely no filter, no morals, and such a strong point of view,” she says, noting how rare it is to find such a fully realized character who’s so unapologetic in her excesses.

That said, she was undecided about whether to take the role when she eavesdropped on Walker’s audition. “She was adorable,” Ritter recalls, which helped seal the deal. Walker, for her part, was such a fan of Ritter’s work in “Breaking Bad” that she admits to gushing “embarrassingly” when she met the actress. “I was obsessed with her being in it,” Walker says.

During a visit to the set on the 20th Century Fox lot just before their fall hiatus, the mood was a bit loopy. Ritter swans onto the set, costumed in a black feather-trimmed robe, singing, “Last day before Thanksgiving breaaaaak,” before adding quickly, “not that I don’t love coming into work every day.” Between scenes of high conflict and broad comedy, Ritter and Walker can be overheard chatting amiably. “You want to run lines, my love?” Ritter asks. “Yes, my pet,” replies Walker.

The episode being filmed has Chloe pretending she and Walker are lesbian lovers to foster a child to use as a free assistant, so Ritter takes the opportunity to grope Walker at every turn. “Dreama’s heaven, she makes me laugh; she’s a good sport,” Ritter says after she honks a body part. She dryly adds, “If we were married, she would definitely be the wife. But we’d both be in skirts. We’d definitely be hot lipstick lesbians.”

Any roommate scenario is going to conjure up “The Odd Couple,” but this particular couple is so far beyond odd, it breaks the template. Costar James Van Der Beek, who plays a hilarious version of himself on the show, likens it to a mash-up of Sid Vicious and “I Love Lucy.” Ritter calls the twosome “A live action ‘Tom and Jerry.’ They’re chasing and chasing, and then finally they settle down and have a nice little moment, and then the cat’s like, ‘Naaah,’ and then it’s back to running.”

Walker has her own take. “I’m standing underneath a horse’s butt and they’re just pouring manure on me, over and over,” she says amiably.

The series has been renewed for a second season, suggesting that the various forms of harassment aren’t likely to stop any time soon. “Chloe never really learns her lesson, and I’m always going to be uptight and concerned about what everyone thinks about me,” says Walker. Adds Ritter, “When you read an edgy script like that, you’re like, ‘Oh, please, it’s never going to fly,’” but Khan reassured her. “She said, ‘Don’t worry, she’ll always be the b----.’”

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