Harry Potter author J.K. Rowling has pledged a major contribution to a $3 million reward for the safe return of a British girl who has been missing in Portugal for nearly two weeks, a newspaper said Sunday.

The News of the World said Rowling had offered the single largest contribution to a reward fund started by the tabloid newspaper. It called Rowling's pledge "staggering," but said the author asked the amount be kept secret.

Madeleine McCann, 4, disappeared May 2 after her parents left her, and her brother and sister, both aged 2, alone while they went to a nearby restaurant within their hotel complex at Praia da Luz, a vacation resort in Portugal's Algarve region. Portuguese police continue to search for her.

The newspaper did not reveal the amount offered by Rowling, but did say that it was larger than a $495,000 pledge from Topshop owner Sir Philip Green.

Tycoon Sir Richard Branson offered $198,000 and American Idol judge Simon Cowell promised to give $99,000.

Rowling, 41, is one of Britain's richest people, with an estimated fortune of $1 billion, thanks to the best-selling novels and films about her boy wizard.

The newspaper said its editor will decide who receives the reward after consulting with Portuguese authorities.