YouTube blogger Zoella has become the fastest selling debut novelist since records began - outselling the likes of JK Rowling and Dan Brown.
Zoe Sugg's novel Girl Online, about a teenage blogger and her relationship with an American musician, sold 78,109 copies in its first week.
It is the highest first-week sale since Nielsen BookScan began collecting data in 1998, according to The Bookseller.
It is the latest in a string of successes for the 24-year-old blogger, who has more than six million subscribers on her YouTube channel.
Such is her popularity that she was invited by Bob Geldof to sing alongside One Direction and Rita Ora on this year's Band Aid song.
Miss Sugg said she was bowled over by the achievement, telling her 2.59 million Twitter followers: "I'm legit blown away by this. I never in a million years thought that so many of you would pick up a copy of Girl Online. Almost wanna cry."
She grew up in Lacock, Wiltshire, and started her Zoella blog in 2009, giving fashion, beauty and lifestyle tips.
She soon became a YouTube sensation and earlier this year signed a two-book deal with publishing giant Random House.
Her first novel was so popular that every bookseller broke the embargo in its sale, according to her publishers.
It hit number three on the Amazon bestsellers list before the book was even released.
On hearing the news, Miss Sugg said: "It's such an amazing feeling. I'm so grateful to everyone who has bought a copy of Girl Online. I love that so many of my viewers are enjoying the book! This year has been so exciting and this for sure is the icing on the cake."
Francesca Dow, Penguin Random House children's managing director, said: "We always knew that the captivating story of Girl Online, and Zoe's fantastic ability to connect with and entertain her audience, had the potential to be an extraordinary combination."
Amy Alward, editorial director of Penguin Children's, said "Zoe is a brilliant role model for young women everywhere - hard-working, dedicated and passionate - and she deserves every ounce of her success.
"In Girl Online she has produced a wonderful, heart-warming novel that addresses some of the most important issues facing teens today, while maintaining the light-hearted, girl-next-door tone that she is known and loved for."
Girl Online's sequel is due to hit shelves next summer.