Giovanni Gallacio was a non-canonical character who appeared in the film adaptation of After the Funeral in Season 10 of ITV's Agatha Christie's Poirot. Giovanni was an Italian art critic who replaces the characters of Pierre Lansquenet and Alexander Guthrie in the original novel. In the film, Giovanni was the husband of Cora Gallacio (Cora Lansquenet in the novel), and unlike Pierre, he was not deceased, only estranged from Cora for some years. Not much is revealed about his backstory except that, like Pierre, he was not welcome at Enderby Hall since his marriage to Cora.
Shortly after the death of Cora, Giovanni turned up at Cora's cottage to help value her pictures, thus filling also the role played by Alexander Guthrie in the novel. Later, Poirot is introduced to Giovanni on the steps of the British Institute of Art. Apparently quite famous, Poirot tells him that he had heard much about him. Poirot invited Giovanni to Enderby Hall along with the rest of the family, to select some keepsake on Cora's behalf before the estate is sold. Like Guthrie, Poirot later asks Giovanni to help prove his theory about the identity murderer. Here, unlike Guthrie, who communicated via telegram, Giovanni actually fetched the painting from Lytchett St Mary to London for examination and then brings it to Enderby Hall for the final denouement.
Giovanni was played by Anthony Valentine in the film. Why the nationality is changed to Italian from the French in the original novel is a matter for conjecture.