“'Only Murders In The Building' boss describes on-screen battle between Meryl Streep and Melissa McCarthy”

Spoiler alert: Major storylines from episode 7 of Hulu's Only Murders in the Building, titled “Valle of the Dolls,” are revealed below.

If someone had told you Just murders in the building If co-creator John Hoffman had gotten Meryl Streep and Melissa McCarthy into a full-on girl fight on the show, he would never have believed you.

The thought itself sounds completely crazy, but in this week's new episode titled “Valley of the Dolls,” currently available to stream on Hulu, it actually happens. Streep's Loretta Durkin and McCarthy's character Doreen, Charles' sister (Steve Martin), have a fight in the suburbs as the latter is desperate and her overtures to Oliver (Martin Short) don't work because the former showed up unannounced.

As Hoffman tells Deadline, the epic fall was originally intended for stunt people, but the veteran actresses wanted to do it themselves, flying braids and all. Find out more about the creepy dolls and how irresistible Oliver is in our questions and answers below.

DEADLINE: You kept Melissa McCarthy's role very secret so that it would be revealed in a hilarious way in episode 7. How did you get cast and did you always know you wanted her to play Charles' sister?

JOHN HOFFMAN: Melissa has been on the wish list for this show for a long time. We've tried to include her in a lot of ways throughout the different seasons, but this season, pretty late at that, it occurred to me, “Oh my God, that's Charles' little sister.” We had one a few weeks before we started filming extensive conversation, and it was one of those great conversations where I introduced the character to her over the phone. I said, “Well, so you play a character named Doreen.” And she said, “I'm in.” Then I said, “You have a doll collection…” And then Melissa asked, “Are you talking about me or the character ?” And I said, “Oh, the character.” She said, “Because you could be talking about me too.” I was like, “Oh my God, okay.”

I told her then that I had seen her very early at the Rose Bowl Flea Market about five years ago. I saw her around 7am, as I didn't know her very well at the time, and she was in a kiosk looking at these very creepy Barbie dolls – they were naked, I think. I wondered if she was thinking about buying the spooky collection. I wasn't sure what was going on so I put it off. After I told her, she said that she bought these dolls entirely for her collection. She said: “This is the greatest conversation I've ever had about a character.” To see her fulfilled like that was just mind-blowing.

DEADLINE: She's such a funny person that I freaked out just at the mention of the word “podcast.” What was it like with her on set?

JH: That was all her! Every time she said Podpourwe all laughed. That was one of the moments where you can imagine me on the monitor; I've never laughed so hard the entire time. Shooting this episode was like a comedy miracle for me.

DEADLINE: Okay, Melissa and Meryl's fierce fight. What happened on set that day?

JH: It was all of them, that was the shock. We had stunt doubles in a season full of stunt doubles. We had to have her on our set that day. So our brilliant stunt coordinator Chris Barnes put together a full living room version of the fight with a couple of (stunt) women so Meryl and Melissa could follow along. I'll never forget it – and here's your big scoop – when I called for Meryl and Melissa to come over to see what the stuntwomen had put together, they both nodded. After watching, they looked at each other and said, “Yes, it's very good, but we want to go much further.”

So they made it their mission to make this scene explode and started working it out together. Every thing they did and every thing they added, I thought, “Wait a minute. You know, we have to do this several times. Are you sure? And Meryl, you're going to turn heads on that couch if you go over there multiple times. What do we do?” They were the wildest thing I’d ever seen. They were thrilled to have overcome this challenge. They made a direct hit every time we shot at that thing. I closed my eyes, Rosy. I thought, “I can’t watch this.”

DEADLINE: So the stuntwomen never noticed anything?

JH: There was one round after (Meryl and Melissa) had done it, I think it was three times that they had done it, then the stunt women came in for a few shots just in case. I think maybe one is in the cut, but other than that it's all (Meryl and Melissa) all the time. And I swear I was so nervous the third time we went through it that I thought I couldn't watch it. If anything happens to any of these women doing this crazy thing they do, I will never forgive myself.

DEADLINE: Did you use stunt pigtails? I was so worried about how they were flying around.

JH: (Laughs) And all the slaps with those pigtails!

DEADLINE: Oliver is the luckiest man in the world as these two women vie for his attention and affection. What is his secret?

JH: What I love about this show is that you see these people that the whole world grew up with, well, depending on what generation you are. It's so cute to see Marty, who is known for playing some pretty ridiculous characters like Jiminy Glick…

DEADLINE: Ed Grimley!

JH: Yes, Ed Grimley. I won't say that they are the most attractive and attractive people who could romantically be the focus of such a pair of women. But the beauty of Marty and the work he does as Oliver on this show is, in many ways, funny and tragic and poignant and funny as hell. I think it's the greatest work I've ever seen from him. Everyone I talked to always said, “I'm in love with that Oliver Putnam guy.” So it makes perfect sense to me. And have you seen this guy's hair?

DEADLINE: The fight wasn't even the biggest moment of the episode. Loretta and Oliver get engaged!

JH: Wasn't that the cutest thing? I'll tell you, one of my favorite parts of this proposal, beyond just Loretta's proposal, is that Meryl brings it up in that moment. I love it. The scene starts with her saying, “So I fought a woman and won,” and she’s so proud. That proposal came about, and it was Marty Short who added the line before “I accept” – and he doesn't do that often: “Is there family money?” It got the most beautiful, sincere reaction and was just the sweetest thing.

DEADLINE: Don't you think a wedding is a great excuse for a murder or the discovery of a murderer?

JH: Wow. Now I wonder about the things we did.

DEADLINE: Speaking of things you've done, what's going on with this new layer of season one plot holes?

JH: Here's what I know: When we do stories like this with the writer's room, it's a really complicated show to write, which is crime fiction in general. But the beauty of it is that you're always going to have a collection of things, like: you went down a certain path, but then it turns out to be nothing, or maybe it doesn't make sense. Where are the things? And at the end of the first season, Mabel (Selena Gomez) stands on the roof and says, “There are just a few unanswered questions.” These are the things that we all know as writers, so we have a lot over the seasons collected from it. I just want to say that it was very exciting to point out certain things from Season 1 because I think a lot of our fans have made lists of some of these loose ends and we want to answer some of them in whole or in part this season. I loved watching the trio pull this off.

DEADLINE: Given these plot holes, could we see the return of some familiar faces from Season 1?

JH: I think anything is possible.