The sari influenced western attire in the early part of the 20th century to some extent – though there was no separation of the bodice and skirt as in India. Elsa Schiaparelli for e.g. was known for her “sari dresses”.
I am assuming this is a gown with a shawl. It has all the elements of a saree in it – the folds of the skirt, the draped cloth over the bosom, the pallu (the loose end of the saree) and the head covering (though the last of this is optional in a saree). I think Ms Baker also has a bindi in keeping with the attire. All in all – as always – she looks quite fabulous.