US Vice-President Dick Cheney will be called as a defence witness in the CIA leak case involving his ex-chief of staff Lewis Libby, defence lawyers say.
Lewis Libby is accused of lying to investigators
Mr Libby faces charges in connection with the leaking of agent Valerie Plame's identity. Her husband had publicly criticised US policy on Iraq.
Mr Libby denies five charges of perjury, making false statements and obstruction of justice.
The trial is expected to start in mid-January.
"We're calling the vice-president," defence lawyer Theodore Wells said at a hearing ahead of the trial in Washington.
Mr Libby is accused of lying to FBI investigators and a grand jury about how and when he learned that Ms Plame was a CIA officer and of lying about disclosing classified information to reporters.
Special Prosecutor Patrick Fitzgerald has been investigating whether administration officials broke the law by deliberately disclosing her identity.
CIA LEAK TIMELINE
6 Jul 2003: Joseph Wilson questions US claims about Iraq nuclear programme
8 Jul: Libby leaks classified information to reporter Judith Miller, but not agent's name, he later testifies
14 Jul: Columnist Robert Novak identifies Wilson's wife as CIA agent
30 Sept: Justice dept launches inquiry into agent's outing
28 Oct 2005: Libby charged with obstruction and perjury
6 Apr 2006: Court papers suggest Bush authorised leak of classified material (not agent's identity)
Last week, he said he did not expect the White House to resist if Mr Cheney or other administration officials were called to testify.
Mr Libby's lawyers had long suggested that the vice-president - for whom he worked as chief of staff at the time - would be irrelevant as a witness in the trial.
Shortly before Ms Plame's name was leaked to the media in 2003, her husband Joseph Wilson had criticised the Bush administration's use of pre-war intelligence on Iraq.
He had been sent to Niger in 2002 to investigate reports that Iraq had bought or had sought to buy uranium there.