Fewest actors in a narrative film

Fewest actors in a narrative film
Who
Sunil Dutt, Shanthi
Where
India
When
1964
Excluding monologues,  the only narrative films with a single cast member have been:- Yaadein (India 1964), written, directed and produced by Sunil Dutt (India), who was also its only actor; La Dernière Lettre  (France/USA 2002) starring Catherine Samie and directed by Frederick Wiseman and Shanthi (India 2004), starring Bhavanaa (India) and written and directed by Baracuru Ramachandrappa (India).

Yaadein is a two-hour film shot entirely in one location and featured cartoon characters and balloons representing other people. The movie's only other living presence is the actress Nargis (Dutt's wife), who is shown in silhouette.

La Dernière  Lettre  runs for 61 minutes and is based on the novel by Vasili Grossman where a woman is locked in a ghetto during WWII and is writing her last letter to her son.

Shanthi  runs for 110 minutes and  is a plea for world peace.