The Baa Baas' game clashes with the Munster v Leinster Magners League derby which will take place on Friday, November 30 at Musgrave Park.
"Contrary to media reports, neither Brian Oâ00Driscoll, Paul Oâ00Connell or any of the selected squads from the Leinster or Munster panels will be available for selection for the upcoming Barbarians match against South Africa on December 1," the statement read.
"The Barbarians were notified of the playersâ00 unavailability for this fixture several weeks ago."
The Baa Baas, who will be coached for the Twickenham tie by Ireland supremo Eddie O'Sullivan, have played South Africa on five previous occasions with their last win being 1994's 23-15 success at Lansdowne Road. O'Driscoll scored a try in the Baa Baas' 41-31 defeat at the hands of the South Africans in Cardiff in December 2000.