The show, set for 20 March, sees two apolitical twenty- somethings adopt the role of Prime Minister and go through a series of policy and PR challenges designed to educate and entertain the public.
Four Communications consultant Christine Warren will be the UK's second ever woman PM, alongside Bristol teacher Nick Langstone-Able.
Each candidate is allotted a press aide and two special advisers to help navigate the muddy waters of Westminster. Warren's back office includes former Fishburn Hedges director Anne Rossitter as spin queen, with Weber Shandwick's joint CEO Colin Byrne and Edelman public affairs director Jo Gibbons providing policy advice.
Langstone-Able's coterie comprises AS Biss consultant and former Amicus comms head Simon Baugh as press aide, and Demos pointyheads Tom Bentley and Will Cavendish as special advisers.
Producer and director Mark Jones tells Diary the brave PROs went through a raft of exercises to test their political and PR nous - though they did benefit from media training by Blair Drummond.
The PMs were interviewed by Fiona Philips of GMTV and Janet Street Porter, and had to decide on policy issues as thorny as any Blair has come up against, including sending troops off to war and working out how to end a painful dispute with petrol retailers.
'The main hitch was getting the time for Kirsty Wark to interview Christine on the Newsnight set,' Jones says.
'It was all set to go when Wark got word that she was able to interview Colin Powell for real instead.'
The Newsnight veteran kindly rescheduled the Warren two-way, which, Diary is assured, is worth staying up for.