NPR’s staid “Tiny Desk” concert series just got juiced.

Singer-songwriter and body-positivity activist Lizzo, 31, brought her signature soulful sass to the typically low-key live music showcase Monday morning.

As fans know, this flute-swinging, proudly plus-size pop sensation doesn’t do subtle.

Twitter’s self-proclaimed “bad b—h” burst into the “Tiny Desk” studio after a far-ranging chat with “Fresh Air” host Terry Gross, and promptly rechristened her gig.

“How we feeling at this, uh, Tiny Ass Desk?” Lizzo quipped as her crowd of 25 people roared in appreciation. “All right, I’m feeling pretty good, too, mmmm. I’ve been wanting to do this for a looong time.”

She had the intimate venue in the palm of her hand from the start: “Can I get an ‘amen’? This desk so damn tiny I can barely fit my thigh underneath it — but we’re so happy to be here!”

The artist born Melissa Viviane Jefferson — clad in a bright orange, off-the-shoulder sweater — performed three live renditions of tracks from her hit album, “Cuz I Love You,” which dropped to much critical acclaim and audience love in April.

“I just want everyone to remember, if you can love me, you can love yourself — every single day,” she told her rapt audience. “If you can love my big, black ass at this tiny, tiny little desk, you can love yourself.”

Highlights from the 16-minute set: Lizzo’s gut-deep rendition of the album’s title track — “Cuz I Love You” — nearly reduced her to tears. “I don’t know what’s come over me, but I’m crying because I love yaaaaa,” she said, flashing a triumphant smile.

After a smooth (“like that s–t?”) segue, she worked up a sweat — literally — with “Truth Hurts.” Finally, armed with her trusty signature instrument (aka “Sasha Flute”), Lizzo blew through a crowd-pleasing performance of her smash hit “Juice.”

Lizzo will next be seen making her big-screen debut as an enterprising stripper in “Hustlers” opposite Jennifer Lopez and Constance Wu. The film hits theaters Sept. 13.

She also expressed interest in doing “The Bachelorette” — if they could meet her X-rated demands.

“It would be mandatory to get my p—y eaten at least once on the whole season, and it would have to be filmed,” she told Cosmopolitan earlier this month. “It can be blurred, but I would want the people to know. The kids gotta learn someday.”