The newest cast member of Outlander season five is here and it is none other than Adso the cat. Sam Heughan (in costume) was the one who introduced the cat who will play him.
Adso is introduced in The Fiery Cross by Diana Gabaldon.
‘Jamie Fraser picks up Adso on the road after the gathering, intending him to keep mice out of Claire’s surgery. Jamie suggests that she name her new pet Adso, after his mother’s cat. Adso takes up semi-permanent residence in a cupboard in Claire’s surgery.” – Outlander Wiki
Lauren Lyle (Marsali) was a bit annoyed to find out there were kittens on set and she was not aware.
Source: Sam Heughan’s Instagram, Outlander on Twitter, Lauren Lyle’s Instagram Story