Reneé Rapp and Lizzy McAlpine Perform 'Wicked' Duet 'For Good' as Glinda and Elphaba

The "Ceilings" singer made a surprise appearance during Rapp's first New York tour stop on her Snow Hard Feelings tour

Reneé Rapp had a "wicked" surprise for fans at her first New York tour stop.

On Monday night during her show at Terminal 5 — just a few blocks fromWicked's Gershwin Theatre — the "Too Well" singer, 23, decided to celebrate the 20th anniversary of the witchy musical in pop star fashion.

In fan-captured footage, Rapp invited indie-folk singer Lizzy McAlpine on stage for a stunning duet of the Wicked classic "For Good," where they took on the parts of Glinda and Elphaba.

The "Ceilings" singer's haunting vocals alternate between Rapp's soulful lilt as they harmonize against a neon green-lit stage.

Related: Reneé Rapp Says Her ‘Insane’ Time on Broadway Prepared Her for ‘Anything’: ‘It Made My Voice a Machine’ (Exclusive)

Rapp's Broadway tribute doesn't come as a surprise.

The actress previously held the role of Regina George in the musical adaptation of Mean Girls, joining initially during a limited run in June 2019 and returning as a main cast member in September of that year before closing during the pandemic.

In an exclusive interview with PEOPLE, Rapp said performing on Broadway at 19 “was like bootcamp,” helping her feel as though “[she] can do anything.”

“Eight shows a week is the hardest thing ever,” the actress said of her time in Mean Girls on Broadway. “I was dying. It's insane, but it definitely– it was like bootcamp.”

She added, “and to point out, I had a princess track, I wasn't doing s---,” referring to a term in musical theater used to describe a role that isn’t on stage for a majority of the show, but is central to the plot. 

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Related: Reneé Rapp Says She’s Found Someone Who 'I Really Love' amid Rumored Romance with a TikTok Star (Exclusive)

The Sex Lives of College Girls star also opened up about the perks that came with learning on Broadway.

“It made my voice a machine,” Rapp said.

She continued: “I figured out how to manipulate my voice in all these different ways so that you can't tell if I don't feel as good one night or the other."

The "Pretty Girls" performer kicked off her Snow Hard Feelings Tour for her debut album Snow Angel Sept. 15, which is currently set to run through March 4, 2024.

Rapp, will reprise her role as Regina in the Mean Girls: The Musical movie adaptation on Jan. 12, 2024.

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