The play, written by the husband and wife team Ruth and Augustus Goetz, tells of a plainyoung woman whose stern father suspects her latest suitor of wooing her for her inheritance.
Two men who knew Capt O'Neill well were Sir Ken Bloomfield, the deputy cabinet secretary, and Lord Kilclooney, who as plain John Taylor became the young Unionist MP at Stormont in 1965.
Campaigners say it will help discourage young people from taking up smoking, but tobacco companies have said plain packs could easily be illicitly copied and the move could lead to job losses.