Portuguese police investigating the disappearance of Madeleine McCann were due to reinterview her mother today.
Kate McCann was due to attend the police station in Portimao in the Algarve this afternoon, accompanied by her lawyer, Carlos Pinto de Abreu.
Her husband, Gerry, will then be questioned by detectives separately at the same police station tomorrow.
It is only the second time Mrs McCann has been formally interviewed by the police, the first being on May 4, the day after four-year-old Madeleine went missing.
Detectives have already questioned her husband twice.
A family friend said the couple were happy to help the police investigation and saw the interviews as a "positive development".
The development comes amid reports that arrests could be imminent following a forensic breakthrough.
Experts at the Forensic Science Service in Birmingham have spent the past month analysing samples taken from the McCanns' holiday apartment in the Algarve resort of Praia da Luz using Low Copy Number analysis.
The technique allows scientists to find a genetic fingerprint from a tiny sample by "growing" it into extra copies that may be repeatedly tested.
Portuguese police have so far given the McCanns no briefing on the forensic results and the official line remains that the tests are still ongoing.
Portuguese police said they were now giving "special attention" to the theory that Madeleine is dead, which depends on the results of the FSS analysis.
Also waiting for details of the forensic tests is the only official suspect in the case, 33-year-old Anglo-Portuguese ex-pat Robert Murat.
He strenuously denies any involvement in Madeleine's disappearance and believes the Portuguese authorities will shortly clear him formally.
Kate and Gerry McCann only heard about the possible forensic breakthrough from a report in the London Evening Standard, and received no briefing from police about it.
Their family spokeswoman said: "The Portuguese police have not phoned Kate and Gerry, and have not told them about the test results. We will await official confirmation as we do for any story.
"Clearly the Evening Standard report may be speculation."
It is understood that the news was "unexpected" for the couple, although they have been awaiting the test results for many weeks.
A friend of the McCanns said: "If you were the parents of a missing child, you would expect that the police would let you know.
"They used to have a good working relationship with the police, but this is bound to affect it."
A spokesman for Portugal's Policia Judiciaria (PJ), who are leading the investigation, refused to confirm the report.