President George W Bush will talk briefly in private with his successor Barack Obama on Wednesday before a rare lunch with all living former US presidents.
The meeting of past and present US leaders is the first such event since 1981 and marks a "historic moment," White House spokeswoman Dana Perino said, amid one of the most delicate transitions in recent memory.
Those around the table will include Jimmy Carter (1977-1981), Bush's father George H W Bush (1989-1993) and Bill Clinton (1993-2001).
Prior to the lunch, the 43rd and 44th presidents will have about a half-hour to meet one-on-one in the Oval Office, with 13 days remaining before Obama is inaugurated to the presidency.
Obama, who will be sworn in as the nation's first African-American president on January 20, inherits two wars in Afghanistan and Iraq, a grave economic crisis, and an upsurge in Middle East violence.
"Tomorrow I'm sure they'll talk a little bit about issues," Perino said, without elaborating.
However, Bush and Obama have spoken regularly, Perino said.
"The president and the president-elect shared a phone call on New Year's Day. They have had periodic calls," she said.