Clarke Gayford grills Baby Done stars Rose Matafeo and Matthew Lewis on their parenting skills

The nation's 'First father' Clarke Gayford has tested Baby Done stars Rose Matafeo and Matthew Lewis on their parenting knowledge (or lack of).

The clip shows Gayford throwing a number of curly questions to the unprepared duo, testing their knowledge of Witches Milk and fontanelle, and posing various parenting scenarios.

"There are more manuals on parenting than grains of sand on earth and still nothing captures what it's actually like," admitted Gayford.

"I tried my best to make it easy, but it was clear when I met them that these two had no chance to getting any of the answers right."

Starring award-winning comedian Rose Matafeo (Breaker Upperers, Funny Girls) and English actor Matthew Lewis (Harry Potter), Baby Done is executive produced by Taika Waititi.

Zoe (Matafeo) freaks out when she becomes pregnant, and while her boyfriend Tim (Lewis) is excited to become a father, Zoe tries to tick as many things as she can off her adventure bucket list before their baby arrives.

Written by Sophie Henderson and directed by her husband Curtis Vowell, the film is a semi-autobiographical look at starting a family.

Vowell says the film grew out of a "fear of growing up and settling down", while Matafeo thinks Kiwis will definitely be able to relate to the film.

"Because Tim and Zoe's pregnancy catches them off guard, their initial instinct is that they haven't achieved enough, which is something lots of people are likely to relate to," she says.

The film is produced by Morgan Waru and executive produced by Waititi and Carthew Neal.