[His] performance in G K Chesterton’s Father Brown (1954) was not only excellent in itself; it provided a nudge on the road to his conversion to Roman Catholicism.
The film was shot in Burgundy. Between takes Guinness, wandering about the local village in his clerical fig, found himself taken by the hand and subjected to the prattle of a local boy, who imagined he was a genuine priest. The confidence which the Church inspired in the child made a profound impression. Guinness became a Roman Catholic in 1956.