Former US president Bill Clinton and best-selling novelist James Patterson are collaborating on a thriller.
The President Is Missing is due to come out in June 2018, according to a joint statement from rival publishers Alfred A Knopf and Little, Brown and Co.
The publishers called the book "a unique amalgam of intrigue, suspense and behind-the-scenes global drama from the highest corridors of power". They said: "It will be informed by details that only a president can know."
Knopf has long been Mr Clinton's publisher, and Mr Patterson has been with Little, Brown for decades.
The President Is Missing is the first work of fiction by Mr Clinton, whose best-known book is the million-selling My Life.
For Mr Patterson, it is the chance to team up with a friend who knows as well as anyone about life in the White House.
"Working with president Clinton has been the highlight of my career, and having access to his first-hand experience has uniquely informed the writing of this novel," Mr Patterson said in a statement.
"I'm a storyteller, and president Clinton's insight has allowed us to tell a really interesting one. It's a rare combination - readers will be drawn to the suspense, of course, but they'll also be given an inside look into what it's like to be president."
"Working on a book about a sitting president - drawing on what I know about the job, life in the White House and the way Washington works - has been a lot of fun," Mr Clinton said in a statement. "And working with Jim has been terrific. I've been a fan of his for a very long time."
A political release from the 1990s had a similar arrangement: Random House and Simon & Schuster jointly published the non-fiction All's Fair by husband-and-wife campaign consultants James Carville and Mary Matalin.
Knopf and Little, Brown declined to offer any more details about the book, including whether it refers to President Donald Trump, who last autumn defeated Mr Clinton's wife, Hillary.
Financial terms for the novel, which the authors began working on in 2016, were not disclosed.
Mr Clinton and Mr Patterson share the same literary representative, Washington lawyer Robert Barnett, who negotiated the deal.
Unexpected news of the day: Bill Clinton and James Patterson co-writing a thriller, "The President Is Missing." pic.twitter.com/tz35ueeoye— John McMurtrie (@McMurtrieSF) May 8, 2017
Presidents and ex-presidents have been turning out books for a long time, but novels are rare.
Jimmy Carter, a prolific and wide-ranging author since leaving the White House in 1981, released the historical novel The Hornet's Nest in 2003.
A presidential daughter, Margaret Truman, had a successful career with her Capital Crime mystery series.
Penguin Random House - which has published both Clinton and Patterson - has UK, Commonwealth and European rights to the collaboration.
"This unprecedented collaboration with its compelling mix of insider knowledge and edge-of-the-seat suspense is utterly irresistible," said Susan Sandon, divisional managing director at Penguin Random House.