Barack and Michelle Obama sign book deals

It is believed the agreements with Penguin Random House could be worth tens of millions of dollars

Barack and Michelle Obama sign book deals

Former President Barack Obama and his wife Michelle. Picture by Steve Helber AP/Press Association Images

Barack and Michelle Obama have agreed to book deals with publishers Penguin Random House.

While no firm details deal have yet been revealed, it had been widely reported that a bidding war between publishers had seen offers in the tens of millions of dollars.

The Obamas are expected to donate a significant portion of their earnings to their charitable Obama Foundation and other charities, The New York Times reports.

In a statement quoted by Associated Press, 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.

"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 the former US President and First Lady are already published authors. Mr Obama wrote the 1995 memoir Dreams from My Father, 2006's Audacity of Hope, and also the children's book Of Thee I Sing.

Mrs Obama, meanwhile, published American Grown: The Story of the White House Kitchen Garden and Gardens Across America in 2012.

A recent study by Kogod School of Business at American University in Washington has estimated the Obamas could earn more than $200 million in their post White House lives.

As well as book deals and their official pensions, speaking fees have proven a major source of income for past US presidents and first ladies.

The Clintons are believed to have earned more than $153 million in paid speeches between 2001 and the start of Hillary Clinton's presidential campaign in 2015.