All Creatures Great and Small returns with the second to last episode of season six, titled Fixes.
In the fifth instalment, James Herriot (portrayed by Nicholas Ralph) takes on the job of attending vet at Hensfield dog track to earn some extra cash.
He's put straight to work, examining the whippets, but soon begins to suspect there might be more going on.
Meanwhile, Tristan Farnon (played by Callum Woodhouse) pays a visit to a family who own an aggressive parrot named George, with whom he shares a personal connection.
Here's everything you need to know about the guest cast for episode five.
The young lad at the race track is portrayed by Frankie Ainley, from the Articulate Drama School and Agency.
Harry, the man in charge of the race track, is played by 57 year old English actor Chris Gascoyne.
He's most recognised for his role as Peter Barlow in Coronation Street.
The father-of-three also has notable roles in Soldier Soldier and New Street Law.
The head of the Ainsley family is played by Yorkshire-born actress Leah Brotherhead.
She's perhaps best known for her role as Toni in the series Hullraisers.
She also lent her voice to Kylie Richards in the audio series The Archers, and had a guest appearance in Bridgerton.
Mrs Ainsley's children are portrayed by Libby and Ralph Falkingham, aged 11 and eight respectively.
They have previously starred in various TV adverts, with All Creatures being their first major credit.

Willie Stockwell is portrayed by Max Runham, an actor who has had guest roles in Casualty, Sister Boniface Mysteries and The Royals.
Tommy Brazendale is played by Joseph Evans, known for his roles as Peter Hoar in Tip Toe and Jackson Hodge in Coronation Street.
Ambrose is brought to life by Philip Joslyn, a Liverpool-based actor whose TV credits include Talamasca, The Responder and Joeys.
Ambrose's friend is played by Graeme Hall, who is actually a professional dog trainer and is known for leading the series Dogs Behaving (Very) Badly.
Known as 'The Dogfather', he has helped celebrities with their pets and is a Master Dog Trainer with the Guild Of Dog Trainers.
All Creatures Great and Small airs on Thursdays on Channel 5 at 9pm
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