Atti has “brains but very little brawn” and when one of his master plans falls foul of Emperor Nero (Craig Roberts), he is sent to dreary old Britain with the Roman army, where the natives are in revolt.
Things only get worse when Atti is captured by Orla, who is desperate to prove herself as a warrior.
Frost plays Orla’s father Arghus, Cattrall appears as his mother Agrippina, Graves as Governor General Paulinus, Kate Nash as Boudicca, Alex Macqueen as Nero’s assistant Sycophantus.
Sir Derek Jacobi meanwhile plays Claudius, an historical figure he first played in the classic 1970s BBC adaptation of I, Claudius by Robert Graves.
Horrible Histories favourites Sarah Hadland, Sanjeev Bhaskar, Dave Lamb, Jessica Ransom and many more also feature, and comic talent including Alexander Armstrong, Lee Mack, Warwick Davis, Lucy Montgomery, Jamie Demetriou, Tony Gardner and Kevin Bishop round out the cast.
The production team behind the TV show will be bringing Horrible Histories to the big screen.
Author of Horrible Histories Terry Deary said: “I am delighted to be so involved in bringing my books to life on the big screen. This could be the most horrible movie you’ll see in 2019. Fans old and new, young and aged will love the horribly hilarious action.”
Horrible Histories: The Movie – Rotten Romans will hit UK cinemas on 26th July 2019