Ashya King's parents have been pictured after their release from custody, and offered thanks to the public for their support.
The couple's lawyer earlier said they would speak about at a news conference in southern Spain - the region where Ashya is being treated - tomorrow.
The National Court in Madrid said in a statement that a judge had ordered the couple's immediate release.
The head of the police force which applied for a European Arrest warrant against the parents of Ashya King has now urged their release.
A British mother whose son's life was saved by proton therapy has told ITV that she defied NHS doctors' advice to pursue the treatment.
The parents of Ashya King said they took him out of a hospital to seek proton beam treatment which is not available under the NHS.