By Jeremy Cooke
BBC, New York
Archbishop Desmond Tutu is to appear in a New York off-Broadway play highly critical of the US handling of detainees at Guantanamo Bay.
Archbishop Tutu will answer audience questions after the show
He will take part in two productions of "Guantanamo - honour-bound to defend freedom", over the weekend.
He will play Lord Justice Steyn, a judge who questions the legal justification of the detention regime.
Once a leading campaigner against apartheid, Archbishop Tutu is a vocal critic of the Guantanamo system.
Now he is taking the unusual step of agreeing to take part in a play which portrays the plight of the British nationals being held without trial along with hundreds of others suspected of being linked with terror organisations including al-Qaeda.
After each performance, Archbishop Tutu will participate in a question and answer session with the audience.
The play, which has drawn warm reviews from New York critics, is a damning indictment of the Bush administration's policies.
Archbishop Tutu's involvement comes at a highly sensitive political time with the US presidential election now just weeks away.