Harper Seven Beckham, newborn daughter of Victoria and David Beckham, may be the ultimate celebrity endorsement.

Amazon.co.uk reports that sales of Harper Lee’s To Kill A Mockingbird have more than doubled after it was revealed that Harper Seven was named after the book’s author.

The fiftieth anniversary edition of the novel currently sits at Number 24 on the Amazon.co.uk bestsellers list.

David explained the name choice on social networking site Facebook last weekend.

“One reason is Harper's an old English name which we loved and one of the other reasons was Victoria's favourite book is To Kill A Mockingbird and the author was Harper Lee. It's a very strong, passionate book. That's where Harper came from,” he said.

The book was originally published in 1960 and is a Pulitzer Prize winner. The Southern Gothic narrative depicts widowed lawyer Atticus Finch defending a black man accused of raping a white woman. An Oscar-winning film adaptation of the book was produced in 1962.