Clarence Mitchell will discuss the response to Madeleine's disappearance from her family's holiday apartment in Praia da Luz, southern Portugal, on May 3 2007 while her parents dined with friends nearby.
Despite a massive police operation and huge publicity worldwide, she has not been found.
Next week, Mr Mitchell will join Mr McCann to give evidence to MPs about how the media reported on the disappearance,
Mr McCann has been invited to answer questions from the Culture, Media and Sport Committee on Tuesday.
They will be joined by Mr McCann's lawyer Adam Tudor, a partner in libel firm Carter-Ruck.
Their evidence will form part of the committee's inquiry into press standards, privacy and libel.
The MPs are expected to ask Mr McCann, 40, why he and his wife Kate, 41, chose to sue a number of British newspapers for defamation instead of going through regulatory body the Press Complaints Commission.
In March last year Express Newspapers agreed to pay the couple £550,000 in libel damages over false allegations that they were responsible for Madeleine's death.
Mr Mitchell said: "I can confirm that Gerry McCann, myself and Adam Tudor from Carter-Ruck will all be giving evidence to the Culture, Media and Sport select committee following an invitation from the chairman to do so."
On the same day the committee will also hear evidence from motorsport boss Max Mosley, who last year won £60,000 in privacy damages against the News of the World over a story claiming he took part in a "sick Nazi orgy".
Robert Murat, the first person to be named an "arguido" or formal suspect in Madeleine's disappearance, took part in a debate about the tabloid press at Cambridge University last night.
His arguido status was lifted last July when the Portuguese authorities shelved their investigation into the case.
He said his life would be "scarred forever" by "tabloid lies".
He argued in favour of the motion "This House Believes Tabloids Do More Harm Than Good" during a debate at the Cambridge Union Society.
"Tabloid journalism has done me and those closest to me real harm. It very nearly destroyed our lives," Mr Murat told the debate.
"And the main reason I'm here is not to express anger or pain, or even to talk about my vindication. It is that I hold out the hope that discussions and debates such as this one may, in some way, help prevent it from destroying the lives of others."
Published by Jon Land for 24dash.com in Communities
Friday 6th March 2009 - 8:48am