The journalism trade publication, owned by Wilmington, is set to unveil its new features-led incarnation in the September issue, available on August 28.
It will contain interviews, comments and features, on an average of 64 pages each issue.
Daisy McAndrew, ITV News economics editor, and Camilla Wright, Popbitch editor, will also be writing regular columns.
There will also be columns on law, money, technology, design and photography, as well as a new freelancing section.
Breaking news is to be published solely on the Press Gazette website.
Reports about proposed changes to Press Gazette have been circulating in recent weeks.
The announcement of the monthly edition comes after Wilmington received a takeover approach last week from a private equity company, believed to be HgCapital.
Wilmington, which owns a range of publications that include Solicitors Journal, Charity Choice and HPCi, bought Press Gazette in 2006, saving the title from closure.
It bought the magazine from former Daily Mirror editor Piers Morgan and PR executive Matthew Freud, who had only owned it for a short time. They had bought the title from Quantum Business Media in 2005.