Sienna Miller, JK Rowling and Max Mosely are all set to give evidence to the Leveson inquiry into press ethics, a day after Kate and Gerry McCann launched a stinging attack on tabloid intrusion.
Miller, a victim of phone hacking, reached a £100,000 settlement with the now defunct News of the World.
The inquiry will also hear from Max Mosely on Thursday. The former president of the FIA won £60,000 in damages from the tabloid after it ran a story claiming he had taken part in a "Nazi orgy".
Harry Potter author Rowling, who has been upset at what she sees as undue intrusion by the media into the lives of her children, is due to be the final witness today.
The first witness to give evidence is protected from being identified by a High Court order and his session will not be televised. It is alleged is phone was hacked while he was in a relationship with a celebrity.
Also giving evidence today is Mark Thomspson, a lawyer who has acted for victims of hacking including Miller and her ex-husband Jude Law.
On Wednesday the parents of missing Madeline McCann hit out at the British media for the way it treated the family following the search for their four-year-old daughter.
Kate McCann told the inquiry she felt "totally violated" by the News of the World after it published her diary without her permission.