Once a month, Anna Lapwood heads to the Royal Albert Hall in London to practice on its grand pipe organ from midnight until 6 a.m. — a rare moment of downtime in the busy venue’s schedule.

Often, the only people who hear her rehearse are the venue’s security staff. But there is another audience that gets to watch her later: Lapwood’s more than 420,000 fans on TikTok.

At the start of each rehearsal, Lapwood props her phone against the organ’s console, so it can capture her every move: her fingers moving rapidly across the organ’s four keyboards, her feet skittering across the pedals and a look of delight spreading across her face as the sounds emerge from the organ’s 9,999 pipes.

When Lapwood has finished playing for the night, she chooses several funny or interesting sections from the footage — such as a vibrant rendition of a movie soundtrack, or the moment she sneezed halfway through a piece — and later posts them on TikTok.

Playing the organ can be a lonely pursuit, Lapwood said in a recent interview. “You’re sitting by yourself onstage, and it can feel like we’re off to one side of the classical music world,” she noted. But whenever she remembers that people are “getting really excited” about her instrument on TikTok, “it feels like, ‘Maybe it doesn’t have to be so lonely.”

Pop stars have long used TikTok to talk directly with fans, show them candid footage of their lives or promote new releases; Lapwood is using the same techniques to inspire TikTok users to fall in love with classical music. While that art form is often seen as intimidating, or unapproachable, Lapwood is trying to make it feel fresh and fun.

Using TikTok, was “about welcoming young people” into classical music, Lapwood, 27, said, adding that was she was continually experimenting with different post types to see what took off. Those clips have included detailed explanations of how organs work and short outtakes of her working the instrument’s pedals wearing slippers in chilly weather. “It’s the best thing I’ve done in my career, in terms of bringing people to the instrument,” she added.

That mission has also extended beyond the app. Lapwood has surprised British commuters by playing a pipe organ that in July was installed on a concourse inside London Bridge railway station, and she has made appearances at pop concerts. In May, musicians touring with Bonobo, a popular electronic act, were in the Royal Albert Hall one night while Lapwood was rehearsing. They were so impressed with her rendition of Bach’s Toccata and Fugue in D minor that they asked her to appear with them at a sold-out show in the same venue the next evening.

The violinist Hilary Hahn, who is also a TikTok user, said that she had been drawn in by Lapwood’s posts and regularly commented on them. “She has a joy about everything she does,” Hahn said. “You get excited about the things she’s excited about.”

For the past six years, Lapwood — who started playing the organ around age 15 — has been the director of music at Pembroke College, part of the University of Cambridge, where her duties include leading two choirs. Just before the coronavirus pandemic began, she noticed some of the female choristers filming a dance routine for their own TikTok accounts. “What on earth are you doing?” she recalled asking, and they urged her to try the app herself.

Her first posts were tentative. (One involved her playing a piece of Bach on the organ’s pedals. She captioned it “Leg day.”) But soon, she was experimenting with clips of contemporary music, as well as sillier ones, like a video in which she showed off her perfect posture by playing a jaunty Bach sonata with rolls of toilet paper stacked on her head. One of her first clips to go viral showed her simply counting down the last 90 seconds before the organ’s bombastic entry in Saint-Saëns’s Symphony No. 3.

Lately, Lapwood has been broadening her music choices beyond the classical repertoire. In February, she posted a clip of herself playing Hans Zimmer’s soundtrack from the movie “Interstellar.” The reaction was so positive, she said, that she started writing her own arrangements of film music, something that she had loved doing as a teenager, but stopped while studying the organ at university because she thought it “wasn’t a respectable thing to do anymore.”

Thanks to TikTok, Lapwood said, she was returning to “a more authentic version of myself,” and now felt freer to experiment with “the idea of what organ playing is, what sounds are expected and what people expect to hear at an organ recital.”

“The organ console is my playground in a way that it wasn’t before,” she added.

Not everyone in the organ world has welcomed Lapwood’s rise. Carpenter said that he knew from experience that many organists feel their instrument should be treated seriously at all times, a view that Lapwood’s posts upend. Some players say that Lapwood is good at raising the organ’s profile, Carpenter said, but are pointedly silent about her musical talent.

On TikTok, Lapwood does get the occasional negative comment — such as a poster complaining about the expressively fluctuating tempo in her performance of a Bach toccata. “Heavy rubato doesn’t belong in Bach,” a commenter wrote, and Lapwood gently hit back in a video.

But Lapwood said that most of the feedback was overwhelmingly positive, with many viewers simply in awe that she plays her instrument with hands and feet.

As Lapwood’s TikTok popularity has grown, her career has flourished beyond the platform. She has performed at the Proms, an annual series of classical music concerts broadcast by the BBC; released an acclaimed debut album; and been named an associate artist at the Royal Albert Hall. In the spring, she is planning a U.S. tour.

Despite that, she is still known as “the TikTok organist” above all else.

Lapwood said that label had once bothered her, because it could “definitely be seen as a derogatory thing, from a certain perspective.” Now, she said, she was embracing it. “I get so emotional when people come up to me and say, ‘Your TikToks have helped me get through a rough time,’ or, ‘I’m now playing the organ because of you,’” she noted.

“So, I am the TikTok organist,” she said, “and that’s OK.”