Rebekah Brooks will appear before the Leveson Inquiry next week.
The former News International chief executive is expected to be asked about her relations with politicians and senior police officers when she gives evidence on May 11.
The press standards inquiry will also receive testimony next week from Lord Rothermere, owner of the Daily Mail and Mail on Sunday.
Further evidence next Thursday will come from Andy Coulson, who became Downing Street's communications chief after quitting as News of the World editor when one of his journalists was jailed in 2007 for phone hacking.
On Wednesday the inquiry will hear from Martin Clarke, editor of the Mail Online, and about police corruption investigations at Scotland Yard and Devon and Cornwall Police.
Mrs Brooks, 43, who edited the News of the World and The Sun, has twice been arrested by Scotland Yard detectives investigating allegations of phone hacking, corrupt payments to public officials, and an attempt to pervert the course of justice. She was bailed and has not been charged.
She has been named as one of the Leveson Inquiry's "core participants", people who have a significant interest in the hearings or may face criticism.
This means she has advance access to documents and witness statements, and the right to put questions to other witnesses through her lawyers.
The Leveson Inquiry's lawyers will not be able to question Mrs Brooks or Mr Coulson, who has also been arrested and bailed, about anything that could prejudice the continuing police investigation into phone hacking or any potential future trials.
Mrs Brooks's evidence could prove embarrassing for Prime Minister David Cameron.
Mr Cameron was forced to admit that he rode a retired police horse loaned to the former News International chief executive by Scotland Yard from 2008 to 2010.
In evidence to the Leveson Inquiry in March, ex-Metropolitan Police communications chief Dick Fedorcio denied a suggestion that he arranged for Mrs Brooks to borrow the horse in return for securing work experience at The Sun for his son.
Mr Cameron set up the Leveson Inquiry last July in response to revelations that the News of the World hacked murdered schoolgirl Milly Dowler's phone after she disappeared in 2002.
The first part of the inquiry, sitting at the Royal Courts of Justice in London, is looking at the culture, practices and ethics of the Press in general and is due to produce a report by October.
Lord Justice Leveson indicated this week that the second part, examining the extent of unlawful activities by journalists, may not go ahead.