SANTIAGO (REUTERS) - Under the watchful eye of prison guards, inmates at the San Joaquin women's prison in Santiago, Chile are rehearsing for the performance of a lifetime: a show for Pope Francis.

Choir participant Margarita Bernal says: "It's a very beautiful and happy occasion because it was done here by the women, who are deprived of their freedom. I am excited to know that the pope is coming."

The women will serenade the pope with a hymn called Pastor with the smell of sheep. They hope it will be a highlight of his four-day visit to their country.

Sister Nelly Leon is leading the choir.

Says Sister Leon: "The first verse is beautiful. It goes, "I am a trapped bird with a hidden pain and with my broken wings. I receive you, pope."

The prison houses some 600 prisoners, many of whom hope his visit will bring them peace and strength as they serve out their time.