British fashion vlogger Zoe Sugg — better known as Zoella — has become the UK’s best-selling debut novelist, shifting more copies in first week sales than J.K. Rowling, Dan Brown, or E.L. James. Her book, Girl Online, is being sold as a "modern day Notting Hill for teens" and follows the adventures of 16-year-old Penny Porter whose personal blog goes viral after she falls in love with a New York rock star.

The novel sold 78,109 copies in the week beginning November 25th, according Nielsen BookScan figures reported by The Telegraph, easily beating Fifty Shades of Grey (14,814 copies in the first week) and Angels and Demons (98 copies). It also handily outstrips the initial print run of 1,000 for the first ever Harry Potter book — although, as with the previous examples, Harry Potter author J.K. Rowling didn’t have a huge, ready-made fan base queueing up to buy her work. (Consequently, it's worth noting that debut sales aren't necessarily indicative of prolonged future success.)

Zoella may not be a name in the literary world, but even publishing executives know better than to ignore her 6.5 million subscribers on YouTube. At the launch of Girl Online, Penguin Random House CEO Tom Weldon said he had been initially skeptical about signing Zoella but changed his mind after consulting his 13-year-old daughter. Weldon is so confident that Zoella is set to publish a sequel in summer 2015, with the publishing exec telling the audience at Girl Online’s launch that he expects to keep selling her books "for many, many years to come."

A review by The Telegraph said the book's message was that "growing up doesn’t have to mean leaving childish stuff behind," before adding that "even Winnie the Pooh might regard [the novel] as a bit twee." Not that it matters, with the sales figures showing that Girl Online is not only the UK’s best-selling debut novel, it’s also the best-selling hardcover title for the entire year. With Zoella selling this fast, expect publishers to be scouring YouTube for potential book deals.