Adam Smith, Jeremy Hunt's former special adviser who was forced to quit after admitting he had inappropriate contact with News International, will give evidence to the Leveson inquiry on Friday 25 May.
Smith will appear on the same day as Frederic Michel, News Corporation's chief lobbyist, who is at the centre of the row over whether Hunt's office gave Rupert Murdoch's company privileged information about its bid to take over BSkyB in 2010.
Also due to appear next week are senior Labour politicians including Peter Mandelson and Tessa Jowell as well as journalists including Jeremy Paxman and Andrew Marr.
The appearance of Smith could be damaging for Hunt - who has always claimed that improper communications between his office and Michel were the actions of his special adviser and not him.
Smith resigned last month after emails provided by James Murdoch to Leveson suggested that he had offered "illegal" advice to News Corporation during its mounting of a takeover bid for BSkyB.
Labour continues to insist that Hunt broke the ministerial code for failing to supervise his political staff.
As a relatively young former special adviser, Smith won't be used to the kind of cross-examination under oath that appearing before Leveson involves. He can expect to be asked whether Hunt was aware of his communications with Michel and the nature of those exchanges.
He will also be asked to comment on claims made by Rebekah Brooks last Friday before Leveson; the former Chief Executive of News International claimed Hunt's office "sought guidance" from the company at the height of the phone-hacking scandal last July - the event which triggered, among other things, the collapse of Rupert Murdoch's bid for BSkyB.
Hunt is also due to appear before the inquiry at the end of this month, with the spectre of being sacked from government hanging over him, depending on what is revealed during his hearing.
Next week also sees a raft of other high profile politicians and journalists called to give evidence to the inquiry into press ethics.
On Monday former business secretary Lord Mandelson will appear, as will the former Labour culture secretary Tessa Jowell.
On Tuesday the former Labour home secretary Alan Johnson will appear along with another former Labour culture secretary Lord Chris Smith and Labour MP and high profile Murdoch critic Tom Watson.
Newsnight presenter Jeremy Paxman will give evidence on Wednesday along with fellow BBC political journalist Andrew Marr.
They will be joined by Lord Reid and former Tory health secretary and current chair of the health select committee Stephen Dorrell.