The parents of four-year-old Madeleine McCann, who was abducted in Portugal four weeks ago during holiday, have announced plans for a "Madeleine Day" to keep her disappearance in the public eye.

Gerry and Kate McCann are planning to feature world leaders, pop stars and well known athletes for the international day of events and appeals to find Madeleine.

Sir Elton John, David Beckham and former US president Bill Clinton are expected to join the appeal.

The McCanns have also approached JK Rowling about distributing bookmarks featuring a picture of Madeleine with her next Harry Potter book.

The couple said that they were praying for their daughter's safety and believes she is still alive because they had no evidence to the contrary.

Last Wednesday, the couple were in Rome to meet the Pope for a "spiritual lift". The Pope blessed a photograph of their daughter and prayed for the family.

The McCanns, who are devout Catholics, also handed out missing posters of Madeleine written in Italian before leaving the country.

Next week the McCanns, after completing a series of appeals in more European cities, will travel to Morocco, where there have been sightings of a girl matching Madeleine's description.

Madeleine vanished 3 May after her parents left her and her siblings alone in their room while they went to a nearby tapas bar inside their hotel complex.