Bill Bailey, who will star in the BBC Christmas production of The Smeds And The Smoos, said the film tackles the older generation’s resistance to change.
The comedian, 57, will be the voice of Grandfather Smed alongside Bridgerton star Adjoa Andoh – who will voice Grandmother Smoo – in the adaption of Julia Donaldson and Axel Scheffler’s award-winning children’s book.
The film will tell a tale about a pair of aliens from two rival groups who fall in love, sparking strong disapproval from their families.
Strictly Come Dancing champion Bailey said: “I think the main themes of the film are that we should just be accepting difference in others.
“I think the thing I get from it is that the older generation tend to be more resistant to change. And actually, sometimes it takes the younger generation to sort of breach that divide.”
Speaking about the underlying themes of the film, Andoh said: “There’s just the sort of the ignorant prejudice that people can harbour about each other until they come together and actually love, and that survival and kinship are the things that bind all of us.”
Bailey, who read Donaldson and Scheffler’s books to his son when he was little, said his character is the “patriarch” of the Smed family.
“He’s very much the kind of protector of the family, and he’s in charge. And he’s quite sort of traditional, and a bit stuck in his ways.
“And he’s sort of a little bit of a stick in the mud, really, but he’s kind. He’s not an ogre. He’s a kindly old grandpa who cares about his family, I think that’s the best way to describe him,” he said.
Meanwhile, Andoh described her character Grandma Smoo as “utterly capable”.
“She can drive a rocket, she can clump about the place, she can blow her trumpet, delight in her kids and her grandkids and she can hate with a passion as well,” she said.
“Grandma Smoo’s not a woman of mild tastes, everything’s fairly strong with her. So when she’s your implacable enemy, she’s implacably your enemy.
“But you could change her mind at any moment and then she will love you to death.”
Sex Education star Ashna Rabheru, who plays Janet, and All American actor Daniel Ezra, who plays Bill, will lead the star-studded cast through a cosmic adventure.
Gavin And Stacey star Rob Brydon returns for his 10th production as Uncle Smoo, with the voice cast also including double Oscar nominee Sally Hawkins as the narrator and comedian Meera Syal as Aunt Smed.
The film will be the latest adaptation of Donaldson and Scheffler’s much-loved books, following on from the likes of The Gruffalo, Zog And The Flying Doctors and, most recently Superworm.
It is being directed by Daniel Snaddon and Samantha Cutler while Barney Goodland and Martin Pope are producers.
Donaldson and Scheffler’s The Smeds And The Smoos will be on BBC One at Christmas.