Kate and Gerry McCann will appear in a Portuguese court on Monday to descibe how they suffered unnecessary grief over accusations in a book that they covered up their daughter Madeleine's death.
The couple will speak at the trial of Goncalo Amaral, the police officer who led the search and who they are suing for libel over the claims he made in his book The Truth Of The Lie, which suggested suggestions that they hid Madeleine's body after she died in an accident and faked an abduction.
She vanished during a family holiday in Portugal in May 2007.
They are expected to deliver emotional statements at Lisbon's Palace of Justice.
Their appearance will mark the end of the trial but a final ruling on the case is not expected until later this year.
Last week, the couple's spokesman Clarence Mitchell confirmed that they were planning to attend court after the judge decided they could speak at the trial after all.
Their daughter Madeleine, who was then nearly four, disappeared from her family's holiday apartment in Praia da Luz in the Algarve on May 3 2007 as her parents dined at a nearby restaurant with friends.
Her parents say that claims in Amaral's 2008 book damaged the hunt for their daughter and exacerbated their anguish.
In October, McCann's sister, Trish Cameron, told the libel trial that the couple's pain over their daughter's disappearance was ''multiplied 100 times'' by the book, and they had been left in ''purgatory'' by the disappearance of Madeleine, and claims that they were somehow involved.
If successful the family stands to gain around £1 million in damages.
The McCanns' court appearance comes after they last week said the fact police found no evidence relating to their missing daughter during recent searches in Praia da Luz had reinforced their belief that she could still be alive.
Mr and Mrs McCann said they were "very pleased" with the significant activity that had taken place in the Algarve resort and it was "gratifying" to know that a substantial amount of work will take place over the coming months.
During searches of three areas of land over 10 days, detectives found no evidence relating to Madeleine, saying the recent activity was only the first phase of the investigation and more would be carried out "shortly".
In a statement, the McCanns said: "We are very pleased that significant activity has taken place in Praia da Luz over the last 10 days with police officers and support teams from the UK working closely with the Policia Judiciaria and the Guarda Nacional Republicana.
"We are further encouraged that despite the intensive searches, no trace of Madeleine has been found and this reinforces our belief that she could still be alive.
"As parents of a missing child, we have always wanted all reasonable lines of inquiry to be followed and it is gratifying to know that a substantial amount of work will take place over the coming months with the close co-operation of the British and Portuguese authorities.
Searches in the Portuguese resort saw officers from Scotland Yard's Operation Grange working alongside specialists from around the UK, including Sussex Police and South Wales Police, with the Portuguese police.