"The Way, Way Back"
Fox Searchlight "The Way, Way Back"

Allison Janney, the perennial scene stealer still best known to this day for her four-time (!) Emmy wining performance as C.J. Cregg on "The West Wing," appears as a supporting player in the Sundance smash "The Way, Way Back" (in theaters this Friday), yet walks away with the film thanks to a ferocious comedic turn that ranks as one of the year's best.

In the Fox Searchlight pickup (the company payed a whopping $10 million for distribution rights), Janney plays Betty, the alcoholic neighbor at a beach-side town who lives adjacent to the film's protagonist Duncan (Liam James), a sullen and introspective 14-year old there on vacation with his mother (Toni Collette) and her emotionally abusive boyfriend (Steve Carrell). A motormouth oversharer with a martini always in hand and tan that skews more orange than brown, Betty is the complete antithesis to the drab Duncan, injecting some real fire into the coming-of-age proceedings dreamed up by "The Descendants" Oscar-winning co-writers Nat Faxon and Jim Rash.

I sat down with a wry and loose Janney in New York to discuss the challenge of playing such a spitfire, her upcoming CBS sitcom "Mom " co-starring Anna Faris, and her time spent on "The West Wing."

I saw this movie at Sundance and I have to say, you were a riot.

Thank you.

I wanted the whole film to be about you. How freeing was it to play a character like that who just says whatever the fuck is on her mind?

I know, it was incredibly -- when I first read that scene, and I don't know if it's my theater training or what, I was like, "I cannot wait to own that scene." Just to take it and run with it, and everyone has to listen to me, it was just so much fun. It was also exhausting. We took one whole day to film that scene.

You mean the first scene?

Yeah, my first appearance of coming off the courts and then going into the kitchen and all that. I thought I was going to die at the end of that day, it was the most exhausting day of acting I've ever done. Because Betty idles at a very high speed and she's pretty exhausting to play. But I loved how she just vomited out of her mouth. Everything just came out. And what I loved most about it was what she was trying to cover up underneath -- the enormous pain and sadness of her husband leaving her for not another woman, for a man, which is just…she's got to feel pretty bad at the start of the summer. I loved it.

And despite the role being a challenge for you, you seem so at ease with a character like that. Did you base her on anybody you know, or is there an element of you in the way she communicates?

"The Way, Way Back"
Fox Searchlight "The Way, Way Back"

There's always an element of me in everything I do. I think this would be me if I went the wrong direction, if I really started to drink too much and stopped being aware of myself and my audience. It would be a tragic me. And I've had different Betty's in my life, those people that are in your life because either of their proximity to you or whatever, and you just have to deal with them. I am always usually the person talking to the Betty at a party. I am always the person who, you know -- someone will drop me and I'll be there forever. I'm too polite, I don't want to be rude to anybody. So she's probably an amalgam of a lot of different people, but I definitely know her. Everybody just has somebody like that that they know. I think everybody will recognize her.

How did you develop the look for the character? Her tacky ensembles no doubt must have helped you embody her.

Oh my god. Well, Ann Roth. When I heard Ann Roth was doing the costumes for this I got so excited. I've had the great pleasure of working with her for many projects, not the least of which was my Broadway debut in "Present Laughter," a Noel Coward play that she did the costumes for. And then I went on and did "The Hours" with her, and then I did "Primary Colors," and there was another one before "The Way Way Back." She's a genius in creating character, and I kind of look to her to tell me who I am a little bit. I love to have other people see who they think Betty is, and I will steal from them and take what works and what doesn't. And we definitely had great costume fittings where it was like, 'No, this is not it, this is not it.' And we would just trust her judgement as well, even though I'm thinking those white pants were a huge mistake [laughs].

Oh no, they were great.

With the cowboy rodeo guy on them. I mean, she's a genius. And then of course the script itself, which Nat [Faxon] wrote, they got the idea for Betty from -- they tell this story about their family getting Christmas cards from people, and one of them has a xeroxed piece of paper inside that says what's been going on with their family for the entire year, and sometimes they share too much information. It's like, why are you telling me about Aunt Sissy's hemorrhoid surgery? They're just sharing too much information. So they thought Betty, every time she opens her mouth, she just tells you too much. Like, nobody asked you how your aunt's doing or how your dog whatever. So that was kind of a fun idea I had in my head when I started playing her. And then every time I would do it they would give me directions, "Try it this way, try it that way," you know. They worked my ass off [laughs].

Next: How to avoid going too broad.