Elizabeth Olsen and Robbie Arnett talk new book, 'Hattie Harmony: Worry Detective' l GMA

We have a great morning here in Times Square. We have some great guests. Because here now, we're with Marvel's very own Wanda, Elizabeth Olsen, and indie band Milo Green's Robbie Arnett. And this morning, the very talented husband and wife duo are revealing their debut picture book to the world, Hattie Harmony, Worry, Detective. Thank you two for coming. I love this. I love a good love connection and a good collaboration. And this is amazing, because I think of you two, they think about superheroes, and they think about hit songs. How do you two come up with a children's book? We've been wanting to write a children's book for, I don't know, I think it's been about four years of us trying to put different books out there for publishers. And it was really meeting a publisher at Penguin, Tamar, who asked if we wanted to write something in the mental health realm, because she liked Robbie's writing. I don't write as much as he does. I'm more the editor. And yeah, exactly. He's more creative with that. And so we both wrote a book. And Robbie wrote Hattie Harmony, and I wrote something else that didn't make the cut. The winning book over here. Yeah, so that's how Hattie came to be, really. And so Robbie, as a musician, I understand that you've actually written some songs about the title character here, Hattie Harmony. How does your experience as a musician, though, translate into this project, writing a book? Well, with music, I usually start with a song title. And so once we had Hattie Harmony, the title, it was just like we had all flowed. And it's just storytelling. And the mantra is really lyrical. The worry, worry, go away. There's no time for you today. It's with you. Yeah, it's catchy. We were hoping that she would also be a reminder for kids, as well, just her friendly face of the mantra, so that it could become something that's more of a supportive blanket for children. Can you talk a little bit more? I mean, writing as a couple, break it down for us how that works. He writes, and I edit, or I have notes. Or he'll create these anecdotes that are helping kids understand the big, complicated feelings that they're having. And then he comes up with a solution, but he doesn't realize that the solution, there's actually a word for it. It's called positive self-talk, or mindful movement. So things like that, I just kind of come in with like the- Yeah, I'd be lost on a tangent if it wasn't for an editor. Well, so it's a perfect harmony. It's a perfect harmony. It's a perfect high harmony. Robbie and I, we're connected here. Click and easy music. But we have a photo of you two around the age of your readers. And I know, Robbie, you moved around a lot as a kid. Are some of the stories in the book related to what happened to you as a kid? Yeah, I remember second grade, walking out first day of school, end of school, seeing all sorts of buses, and didn't know which bus I was going to get on. And so I was overwhelmed, feeling really vulnerable. And so that's a bit in the story, and how you overcome that. And it's OK to feel vulnerable, and it's courageous. And so all of those moments are in the book. And the first day of school, we have the first- it's a series, and the first book is the first day of school. Well, you had a lot of first days of school. I had a lot of first days of school. Yeah, so it's all reflected. Which is all scary. Yeah, it's a scary moment. But we're all capable of- if we can identify, that's the thing that we kept going back to, is if children are able to at least identify the length, like the word of what they're feeling and how they're feeling, then maybe they can also identify it in someone else, and have a little bit more compassion or empathy or curiosity. And so that's not just about figuring out our own behavioral patterns, but the people around us as well. Yeah, even at that tender age. Yeah. She gets around. She does. Rome, a baseball game. Well, we bleed blue. Or Dodgers. Be specific. But that's another thing to say. She's universal. She gets around. Yes, we happen to be on a holiday, and Hattie comes with us wherever we go. Yeah, Hattie's at GMA right now. Oh, I love that. Hey, there you are. Robbie's learned how to TikTok from Hattie. We're learning a lot of new skills with Hattie. I knew you had something when you came in here. That's her. Now we know. Elizabeth, before we got to get to this, because we have to ask about the multiverse. I got a list of things the fans want to know about. Of course, the WandaVision spinoff, Agatha House of Harkness, that is coming up. Rumor has it that you're getting your own standalone Scarlet Witch movie. Are you able to talk about any of this stuff? I would love to be a part of both of those. No one tells me anything, and I'm not even hiding a secret, because I'm bad at that. I know nothing about my future. They are very good at locking that info up. These were fan requests. They needed to know. So, okay, got it. And I'll be honest, that was the answer we expected. No one can tell us anything. But what they can tell us, and what we can tell you, is make sure you go out, pick up Hattie, Harmony, Worry, Detective. It is available now. I love you two, and I love you for coming and sharing this story. You guys are inspirational to all of us. Well, hey there, GMA fans. Robin Roberts here. Thanks for checking out our YouTube channel. Lots of great stuff here. So go on, click the subscribe button right over here to get more of awesome videos and content from GMA every day, anytime. We thank you for watching, and we'll see you in the morning on GMA.