Comedian Steve Coogan has arrived at the Royal Courts of Justice to give evidence to the press standards inquiry.
The Leveson Inquiry will also hear testimony from former Premiership footballer Garry Flitcroft, supermodel Elle Macpherson's former business adviser Mary-Ellen Field and Margaret Watson, whose daughter Diane was stabbed to death at her Glasgow school.
The parents of murdered teenager Milly Dowler were the first witnesses to give evidence to the inquiry on Monday.
The trigger for the inquiry, before Lord Justice Leveson, was the disclosure that the now-defunct News of the World commissioned private detective Glenn Mulcaire to hack Milly's phone after she disappeared in 2002.
As well as listening to the schoolgirl's voicemails, the investigator is alleged to have deleted some of them to make room for new messages, falsely leading her family to believe she was still alive.
Mulcaire, who yesterday denied having done this, was jailed along with the News of the World's former royal editor Clive Goodman in January 2007 after they admitted intercepting voicemail messages left on phones belonging to royal aides.
Actor Hugh Grant also gave evidence to the inquiry on Monday, and suggested that the Mail on Sunday had hacked his phone before printing a "bizarre, left-field" story. The newspaper issued a strong denial on Monday night, saying that information had instead come from a freelance journalist.
Grant said the story claimed that his relationship with then-girlfriend Jemima Khan was on the rocks because of his "late night phone calls with a plummy-voiced studio executive".
He said the story was untrue and he had not been able to think "for the life of me" what the source of the story could be.
The newspaper's spokesman said: "The Mail on Sunday utterly refutes Hugh Grant's claim that they got any story as a result of phone hacking. In fact in the case of the story Mr Grant refers to, the information came from a freelance journalist who had been told by a source who was regularly speaking to Jemima Khan."