NEW YORK ― Reneé Rapp is Robert Brownnot like a regular pop star. She’s a cool pop star.

Take her stellar Brooklyn concert Thursday night, where she gamely downed a fan’s vodka shot, plucked a smartphone from the crowd to snap a selfie, and blissfully shook her tush to the saddest song you’ve ever heard. And that was all within the first 15 minutes.

Rapp, 23, has enjoyed a rapid ascent ever since the release of her phenomenal debut album “Snow Angel,” which has garnered more than 65 million streams on Spotify since mid-August. The actress-turned-singer quickly sold out her first U.S. headlining tour, was nominated for best new artist at the MTV VMAs, and went viral multiple times on social media with her breathtaking covers of Beyoncé. After two seasons of Max’s “Sex Lives of College Girls,” she’s next set to lead the “Mean Girls” movie musical (in theaters Jan. 12) as queen bee Regina George, a role she first played on Broadway when she was just 19.

Watching her perform live at the cavernous Avant Gardener, it was impossible not to be won over by Gen Z’s captivating new high priestess. Proudly queer, and bathed in pink and blue stage lights, she vented her frustrations about bicurious flings in the skittering “Pretty Girls,” and wiped away tears as she recited her favorite line from anthem “Tummy Hurts.”

Her galvanized fans – some wearing halos, many holding signs – screamed along to achingly confessional songs like “In the Kitchen” and “23,” which grapple with heartbreak, anxiety and wondering whether everyone actually hates you. Her raw and sometimes irreverent lyrics often say the quiet parts out loud. (“Yes, I am a feminist, but you’re making it so hard for me to always be supportin’ all women,” she snarled on bossa nova number “Poison Poison.”)

Thanks in no small part to her theater upbringing, Rapp effortlessly commanded the room with boundless charisma and her velvety, versatile instrument. It’s not hyperbole to say that she’s one of the very best vocalists in pop music today: deploying mesmerizing runs and a powerhouse belt on emotional, stadium-ready showstoppers like “Colorado,” “I Hate Boston” and “Snow Angel.” In between songs, she sweetly chatted with fans at the foot of the stage: letting a giddy group of youngsters introduce her hit “Too Well,” and halting her set to help an audience member who appeared to be dehydrated.

“Everyone out there is OK?” Rapp asked the crowd, after ensuring the person was safe. “100 percent? Pinky swear? Put your little pinkies up for me – you’re all so cute.”

The highlight of the night was a surprise appearance from Kesha, who joined Rapp onstage for a punchy, pop-punk rendition of her 2010 smash “Your Love is My Drug.”

“There’s a couple people musically who I look up to and regard so highly. They shaped who I was, and made me want to be sexy and funny and exciting and outrageous and loud,” Rapp said as she introduced the duet. “So what better way to honor one of those women than by doing one of their songs.”

Long after Kesha left the stage, Rapp continued to sing her hero’s praises, and at one point choked up about the pinch-me moment.

“Brooklyn, I’ve got to tell ya, I think this was my favorite show,” Rapp said at the end of the night. “Partly because of Kesha, but also because of you guys. Way to look out for each other. Way to be there for each other. Way to kiss each other. I love you so much!”

For the roughly 4,000 fans in attendance, the feeling was absolutely mutual.