Gordon Brown will be called to give evidence to the Iraq Inquiry before the general election, the BBC understands.
The prime minister had been due to appear before Sir John Chilcot's inquiry after the election - due by June at the latest.
But he has been under pressure from opposition parties to explain his role before voters go to the polls.
Mr Brown was chancellor at the time of the 2003 invasion and has said he will be "happy" to appear whenever called.
BBC deputy political editor James Landale said it was not yet known if whether it was Mr Brown or Sir John who had decided to call for an earlier appearance.
'Signed the cheques'
But he said Labour would be keen not to let the potentially damaging row rumble on up until the General Election.
Last week Liberal Democrat leader Nick Clegg had told Mr Brown people were entitled to know what his role had been before they voted as he had "signed the cheques".
At prime minister's questions on Wednesday, Mr Brown told MPs he had written to Sir John saying he was happy to appear "at any time" before the committee - but it was up to the independent panel to decide.
In his letter to Sir John Chilcot, Mr Brown wrote: "I am clear that it is a matter for you how you conduct the inquiry and that it is, and must remain, entirely independent of government.
"In undertaking this, you have rightly chosen the order you wish to receive evidence.
"For my part, I want to make it absolutely clear I am prepared to give evidence whenever you see fit. I remain happy to take your advice on this matter."
Mr Clegg had said that was not enough and Mr Brown should "insist" on giving evidence before the election - widely expected to be called on 6 May.
Inquiry chairman Sir John had indicated that hearings would not be held in the run-up to the election to allow the inquiry to remain outside party politics.