We're heading back to the Yorkshire Dales on Thursday night for the brand new season of Channel 5's heartwarming period drama, All Creatures Great and Small.
Nicholas Ralph and Rachel Shenton will reprise their roles as James and Helen Herriot, alongside Samuel West's Siegfried Farnon and Anna Madeley's Mrs Hall. However, one beloved cast member who won't appear in season four is Callum Woodhouse, who portrays Siegfried's mischievous younger brother, Tristan.
So, why isn't the actor returning for the new series? We've done some digging and here's all we know…
Why isn't Tristan actor Callum Woodhouse in All Creatures series four?
At the end of season three, Tristan left Darrowby after he was called up to serve in the Royal Army Veterinary Corps, which means the character won't feature in the new episodes.
While it's likely that Callum, 29, simply didn't appear in the series due to his character's storyline, it's possible that the actor had other filming commitments to fulfill.
The Durham-born actor is set to appear in a new mystery-horror, titled One Of Us, and will star alongside Heartstopper's Kit Connor and Game of Thrones actress Charlotte Hope. Filming for the upcoming movie began in Belfast in March, which is the same month filming began on All Creatures season four – so it's possible that there was a clash in production schedules.
While we don't know whether Callum will return for future seasons – which Channel 5 has yet to announce – an Instagram post that he shared after the show's emotional 2022 Christmas special hints at his return.
Posting a behind-the-scenes snap of him and his co-star Samuel posing with season three clapperboards, Callum wrote: "Over n out for now, thanks for everything."
Fans rushed to the comments section to praise the actor's performance, with many expressing sadness over his character's departure from Darrowby. One person wrote: "I'm sorry but I cannot bear the thought of having all creatures without Tristan. In the old series, they all came back from the war so please Callum come back or I'll go cry myself to sleep."
A second viewer added: "I was not emotionally prepared for that but a wonderful Christmas treat to have ACGAS on screen again. Tristan has to come back, he's my favourite!"
Fans aren't the only ones sad to see Tristan go, however. Callum's co-star Nicholas Ralph opened up about feeling his absence on set in a recent interview. "The character James misses Tris, but also we missed Cal on set and hanging out," he told RadioTimes.com. "He's a wonderful, wonderful actor."
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What happens in All Creatures Great and Small series four?
The new episodes pick up in the spring of 1940, with change on the horizon for Skeldale House.
With James uncertain whether or not he'll be called up to serve in the RAF, he and Helen wonder when the right time might be to start a family.
Meanwhile, Tristan's absence is felt by all, but especially by his older brother Siegfried, who "attempts to hold the growing household, and himself, together as he braves this new world," according to the synopsis.
"Mrs Hall and Helen’s friendship blossoms as they look to the future and new trainee veterinary student Richard Carmody arrives, causing complications in the house."
All Creatures Great and Small returns on Thursday, October 5 at 9pm on Channel 5.