With two No. 1 albums on the Billboard 200 and four entries on the Hot 100, it’s undeniable: Pentatonix is a force. While those feats are impressive on their own, add to it that they’re an acapella group and the success is unparalleled. At the heart of the band are Mitch Grassi and Scott Hoying -- who also have their side project, Superfruit.

Boasting nearly 2.5 million subscribers on their YouTube channel, the friends have vogued in a ball pit and taught Papa Grassi gay slang. Even on the phone, their peppy, strong dynamic boils over. Ahead of the duo's debut EP release, Future Friends - Part One (out June 30 and available now for pre-order), Billboard talked to the guys about their close friendship: "we have 60 million inside jokes that we can just pull up at any time."

How did you two meet?

Mitch: We met in theater in Arlington, Texas. Our first play together was Annie.

Scott: And then we went to separate schools for around a year and a half and we were reunited.

Were you two best friends the first time you met or did it kind of progress?

Mitch: We weren’t immediately best friends, but there was definitely, like, a match to us.

Scott: I thought we were like best friends.

Mitch: Yeah, that’s true. We were pretty giggly together.

What were your first impressions when you met?

Mitch: I remember thinking Scott was really, really funny and very enthusiastic.

Scott: Aww!

Mitch: He was like the singer at our theater.

Scott: I remember being in Charlie and the Chocolate Factory with Mitch. And he was like, performing the monologue really, really full-out, and like running across the stage with his arm reached out -- I specifically remember the image in my head -- and I remember thinking, ‘Wow. He’s really good.’

Mitch: Thank you.

How did you two become so close-knit?

Scott: I think we both just thought we were super funny.

Mitch: Yeah.

Scott: And we just had all of the same interests.

Mitch: We were both nerdy, we were both singers, we were both performers, both in the closet…

Do you think that element added a special bond to your friendship, having that connection in identity?

Mitch: Oh, absolutely. Yeah. Just because we were super comfortable around each other. Even while we were in the closet, there was still that comfortability. We just sort of subconsciously knew.

Scott: Yeah! We just felt really comfortable around each other, and I think that now we could say why, but back then it was just sort of a subconscious thing. I’m a big talker. I talk a lot. And Mitch is good at listening, and that’s always been a good thing for us.

What makes him your best friend?

Scott: Well, a lot of things. We just have such a history. We have so many memories together, and I think that we feel more comfortable around each other than we do than around anyone in the entire world.

Mitch: Yeah, that’s true too. We know each other so well. I don’t know anybody as much as I know Scott. That bonds us even more.

Scott: And we have 60 million inside jokes that we can just pull up at any time.

Mitch: Right. We grew up together. I mean, we forged our career paths at the same time.

Scott: I feel like we’ve lived a very unique lifestyle being in an a cappella group that’s really successful. That’s a very rare lifestyle to live, and we’re living it together.

What makes your best friend one-of-a-kind?

Scott: I think that Mitch is just insanely talented. He's hilarious, so goofy, so humble. Like, he doesn't act humble, but he actually is really humble. And someone who is talented is not usually that way. I’m not that way.

Mitch: No, you’re not.

[Both laugh.]

Mitch: Scott is insanely talented as well. But he's also such a sharp entrepreneur and a businessman.

When and why did you decide to create Superfruit?

Scott: We were just having the best time -- always laughing, joking. We had friends who would come over and compliment on our dynamic and our friendship, and they were like, ‘I wish I had a friendship like yours.’ And I think that we just, like, decided that we wanted to show it to the world, our personalities. Because people knew us from our audition, and they knew we had personalities outside of that. We both wanted to start YouTube channels, but we were both too scared to do it. I think the reason our YouTube is successful is because of our dynamic.

How would you describe your dynamic?

Scott: I think it’s just a genuine friendship.

Mitch: We don’t really necessarily say what we’re thinking, but we know what the other is thinking, so it’s just nonstop words and catchphrases and inside jokes one after another and we’re constantly laughing.

Scott: It’s just kind of fun to watch even if you don’t know what we’re talking about.

How does it feel to perform together instead of with the whole group?

Scott: We performed at Betty Who’s concert with her and it was kind of thrilling. It was scary.

Mitch: It was scary.

Scott: We’ve performed hundreds and hundreds of shows constantly with Pentatonix, so we have this very specific dynamic that we’re used to and comfortable with on stage. With Superfruit, I remember before we went out with Betty [there were] butterflies back stage, because it’s just so different. I think it’s more scary when you don’t have five people.

So much fun joining this queen on stage tonight! Thank you for letting us be part of the show tonight! We ?? you @bettywho! A post shared by SUPERFRUIT (@sup3rfruit) on May 3, 2017 at 12:43am PDT

Mitch: Absolutely.

Do you think you would perform together again in the future?

Scott: Absolutely. We were just talking about it today.

Years ago, you two did a best friend challenge, seeing if you knew each other's favorite things. You both did well, but we want to see if you've still got it. Let's start with Mitch: what is Scott’s favorite color?

Mitch: Scott’s favorite color is blue.

Scott: Yes!

Mitch: Ah-ha!

What is Mitch’s favorite color?

Scott: Chartreuse.

Mitch: Yes!

What is Mitch’s favorite animal?

Scott: I think this changes a lot, but I think it’s over all a fox.

Mitch: Yes.

What is Scott’s favorite animal?

Mitch: I think he just likes dogs.

Scott: Yeah. I like dogs.

Mitch: Wow!

Scott: We’re killing it.

Who takes more time to get ready?

Mitch: Me.

Scott: Oh, definitely Mitch.

What is Scott’s favorite Broadway musical?

Mitch: Oh, I know it… It’s Wicked.

Scott: Wicked will always hold a special place in my heart.

What is Mitch’s favorite Broadway musical?

Scott: Rent.

Mitch: That’s correct.

What is Scott’s favorite movie?

Mitch: The Eternal Sunshine of the Spotless Mind.

Scott: Yeah.

What is Mitch’s favorite movie?

Scott: Spirited Away.

Mitch: Yeah!

Mitch’s favorite cartoon?

Scott: SpongeBob for sure.

Scott’s?

Mitch: Family Guy.

Scott: Oh, duh.

What is Mitch’s dream vacation?

Scott: Mitch’s dream vacation is probably Paris.

Mitch: Yeah, I would say so too.

What is Scott’s dream vacation?

Mitch: I’m going to say Bora Bora.

Scott: Yup! That is correct.

Does Mitch do anything weird?

Scott: Yeah. He does all sorts of weird things. He watches videos of people whispering every night to relax him before he goes to sleep.

Does Scott?

Mitch: Whenever Scott gets uncomfortable… or he’s just trying to make the situation better, he’ll go uh-umm [sings a melody.]

Scott is going to get fast food. What does he get?

Mitch: I feel like you would get Chick-fil-A, right?

Scott: Or Taco Bell.

Mitch: Or Taco Bell.

What would Mitch get?

Scott: You would get Chick-fil-A.

Mitch: Yeah, or Taco Bell.