Religious belief is usually a private affair, but movie actors and directors are public figures, and this week there has been a resurgence of that notable phenomenon, the "Hollywood conversion". Sean Stone, the 27-year-old son of director Oliver Stone, has become a Shiite Muslim during a visit to Iran; he is working on a documentary about the 13th-century Persian Muslim poet and mystic Rumi. Liam Neeson, in Istanbul filming a sequel to his hit thriller Taken,, was quoted by the Sun as saying: "There are 4,000 mosques…t really makes me think about becoming a Muslim."

Announcing religious views in this way can be tricky. In 2010 Julia Roberts announced her conversion to Hinduism in such a way as to suggest that making Eat Pray Love had sent her over. Later, Roberts became irritated at the association, insisting that her interest in Hindism pre-dated her involvement in Eat Pray Love. Richard Gere is a notable adherent of Buddhism and Madonna switched from her cradle Catholicism to Kabbalah in the late 1990s. Elizabeth Taylor converted to Judaism in 1959; there was industry gossip that playing a Jewish character in Ivanhoe had partly inspired her. Perhaps the most sensational conversion in recent times is that of the screenwriter Joe Eszterhas, famed for sexy thrillers like Basic Instinct, who converted to Catholicism after a diagnosis of cancer, and has been commissioned by Mel Gibson to write a biblically themed script.

These are notable conversions; and Hollywood figures are no more susceptible to backsliding or second-thoughts than ordinary mortals, though it is worth bearing in mind that unlike marriages, religious commitments are not legally expensive to annul. A religious conversion on a film location may look rash: and yet as François Truffaut indicated in his film Day for Night, a film set is like real life only much realer. If Stone finds enlightenment filming, who is to say that this is less enlightened than anyone else's conversion?