Just three weeks before tart-tongued Joan Rivers (with daughter Melissa) takes her rightful spot outside Hollywood’s Kodak Theatre to critique celebrity Oscar fashions, she’s added a new wrinkle (the only one she won’t attack with Botox) – her first novel, “Murder at the Academy Awards” (Pocket).

In what she hopes is the start of the “Red Carpet Murder Mystery” series, Rivers and co-author Jerrylyn Farmer skewer Hollywood’s most glorious and overwrought night, as Oscar nominee Halsey Hamilton – “tabloid princess du jour” – collapses and dies on the red carpet clad only in pink satin thong and jet-black bra

Rivers’ fictional stand-in, Maxine Taylor, gets the final, exclusive Halsey interview. But her last words indicate she was murdered, and Max’s daughter/partner Drew may be involved! To clear her daughter, Max winds her way through the Vanity Fair Oscar party, celebrity rehab and other Hollywood institutions.

Before we got down to the book, first we had to ask Joan . . .

Who are you wearing?

Right now I’m wearing Chanel pants. Black, of course. And a Donna Karan sweater. Black, of course. Joan Rivers jewelry, of course. And red Manolos. Oh wait, and Bernie Madoff sent me the most beautiful bracelet – from nowhere. How sweet is that. I don’t even know the man, I got this big bundle of jewelry.

Did Melissa read it before you published it?

No. I just said to her: “Trust me.” And she did. And I think Drew comes out just fine and dandy. The bad characters were a couple of guys that I didn’t like that Melissa dated.

Are there any mystery writers you look up to?

Barbara Taylor Bradford is a friend. And I also wrote a movie with the late great Donald Westlake [the non-produced murder mystery “A Girl named Banana”]

Is there anyone you’d like to have seen murdered at the Academy Awards?

Oh where do you start? I would love to have seen Russell Crowe murdered. I would love to have seen Tommy Lee Jones murdered. And both of them by the way, you can never find them together because so many people dislike them. Diane Keaton passes me by, after I wrote a chapter in her stupid book on clowns.

What did you hope to show in the book?

I just wanted to get in the horror of what’s going on backstage at the Academy Awards. We hope it’s a series. I can’t wait to do “Murder at Sundance,” and how about “Murder at Cannes,” Murder at the Country Westerns,” “Murder at the Porn Awards” . . .

Did you have to do any research. For example, all the rehab scenes seem pretty spot-on.

They are spot on. I had a friend who was in one of them. And Melissa’s had several friends. So, none of it was foreign to me. I mean, you know, write what you know. And we really wrote what we know.

There’s a scene in the book where Britney Spears is reading Scripture at Halsey’s funeral – at the Kodak theatre. It’s hilarious.

I find it hilarious that she can read.

Tell me a very weird thing that’s happened to you on the red carpet.

Well, literally, the woman from BBC – and everyone is so frah frah frah, you know – Nicole Kidman came over to me, and she started to take her away on the air, and I punched her, on the air.

Where did you punch her?

Right in the stomach. No, she’s mine! Bang. Right in her sequins.

You’re tough.

You have to be. At the Academy Awards, they have the shrubs, you have to lean over to talk to people. After the first year, I brought clippers. I used to cut the shrubs down. It’s all about how many [stars] you get and who passes you by and who started to talk to you and walked away. And who’s a sh – – and who’s nice. It’s so exhausting. And it all comes down to, like they talk about in the book, “How many did you get?”

Is it really that backstabbng on the red carpet?

I thought I was very kind. Oh, it’s a bloodbath. My joke is: The red carpet started out white; it’s the blood on it. Are you kidding?

Has anyone ever passed out in front of you on the red carpet?

I’ve had somebody so drugged that they fell asleep while talking to me – a male singer. And I’ve had a couple making out disgustingly in front of us one time, you just go: Come on . . . we’re so in love. And meanwhile two years later, of course, they’re broken up.

Are celebrities really crazy?

They’re nuts. And it’s wonderful that they’re nuts. The ones I don’t like are the ones that take themselves seriously.

Academy Award predictions?

I just don’t want any good Nazis to win. “The Boy in the Striped Pajamas,” the mother’s a good Nazi – her husband’s burning Jews. The woman in “The Reader,” she killed 300 Jews, but she learned to read so she’s good. “Valkyrie,” he wanted to . . . They’re all good nazis. It makes me laugh. “Oh, here’s the good Nazi movie.”