It's reported that former President and First Lady Barack and Michelle Obama are about to sell their memoirs for a record fee.

A bidding war has broken out between several prominent book publishers, according to a person involved in the sale process.

A deal is expected to be announced sometime this week, the source told CNN.

According to the Financial Times, at least one of the bids surpassed $60 million (€56 million) which is "a record sum for US presidential memoirs."

Both the former president and the former first lady are writing books about their time in the White House. The pair of books will be published separately, but publishing houses like Penguin Random House are bidding for the books together.

It is unclear when the books will come out.

Lawyer and literary agent Bob Barnett, who is representing the Obamas for the joint book deal, declined to comment. Obama spokesman Kevin Lewis also declined to comment.

Former President Obama's past books were published by Penguin Random House. The FT said Penguin "is leading the pack for the Obamas' joint publishing deal."

Another publisher, Crown, reportedly paid about $10 million for the rights to George W. Bush's White House memoir.