Barack and Michelle Obama have signed book deals worth a reported $60m with Penguin Random House following a bidding war among a number of publishers.

The former president and first lady are intending to donate a 'significant portion' of their book earnings to charity. Although the financial details of the book deals were not released, people briefed on the auction say they will exceed $60m (£48.2m), the Financial Times reports.

In a statement, Penguin Random House CEO Markus Dohle said: "We are absolutely thrilled to continue our publishing partnership with President and Mrs. Obama.

"With their words and their leadership, they changed the world, and every day, with the books we publish at Penguin Random House, we strive to do the same.

"Now, we are very much looking forward to working together with President and Mrs. Obama to make each of their books global publishing events of unprecedented scope and significance."

Both of the Obamas have previously released books with Crown, whose parent company is Penguin Random House, and industry insiders told the New York Times it is likely the recent deal with the publisher is worth tens of millions of dollars.

Indeed, Barack Obama's book advance is expected to be among the largest awarded to former US presidents.

The pair were represented by Robert Barnett and Deneen Howell of Williams & Connolly during the book deal, with Random House pledging to donate a million books to their non-profit partner First Book as part of the agreement.

No titles or book release dates have yet been made available to the public, although Barack Obama is expected to be making a return to the political stage alongside his book-writing activity.