Pentatonix members Scott Hoying and Mitch Grassi were still riding high from just working with Dolly Parton when they found out they helped her break a Billboard record.

“It was unbelievable,” Scott told ET at the 6th Annual Streamy Awards in Los Angeles on Tuesday.

Last week, Dolly became the first artist to ever land a top 20 hit on Billboard’s “Hot Country Songs” chart in each decade since 1969. It’s all thanks to her new collaboration with Pentatonix, an a cappella remake of Dolly’s classic, “Jolene.”

WATCH: Reese Witherspoon Fangirls at Dolly Parton’s Los Angeles Show

“She is such a legend, and she's so kind,” Scott adds. “When we walked into the room to work with her, the first thing she said was, 'Pentatonix, it's such an honor to work with you guys,' and we just melted to the floor, because we're such huge fans. It's been an amazing couple weeks.”

Mitch shares that, while Dolly didn’t give the band any specific advice, they did take notes from the living legend.

“Just her career trajectory, and who she is as a person is inspiring enough, honestly,” he says.

Mitch, Scott and their Pentatonix bandmates will follow up “Jolene” with a new Christmas album, A Pentatonix Christmas, set to be released later this month.

“This one is a little weirder than our last one,” Mitch teases. “[There’s] some surprises and some treats on the album. But it's definitely still that signature Pentatonix jolliness.”

WATCH: Behind the Scenes of Pentatonix’s Christmas Video Shoot

“We got very creative,” Scott continues. “I'm very proud of this one, especially a couple of the tracks are my favorite Christmas music we've ever made, and there's two originals, which is cool.”

The longtime friends are also focused on their YouTube channel, Superfruit, and promise a lot of exciting content coming soon.

“Nothing that we can specifically talk about yet, but a lot,” Scott confesses. “Every avenue of the entertainment industry, we're trying to dip our toes in.”

Last year, ET caught up with Pentatonix while they were touring with Kelly Clarkson. Check out that chat in the video below.