The BBC has announced details of one of its most ambitious TV science projects - Walking With Cavemen.
Actors spent five hours in make-up each morning
The £4m series, a follow-up to Walking With Dinosaurs and Walking With Beasts, explains the story of human evolution.
Presented by Professor Robert Winston, the four-part series starting on BBC One on 27 March uses the latest technology to bring prehistoric worlds to life.
It takes the viewer back three-and-a-half million years to explain how modern man evolved from a common ancestor with apes, and ends 30,000 years ago when our ancestors split into two populations.
More than 100 scientists were involved in the project, which was filmed on location in South Africa, Iceland and the UK.
Actors are used to portray the different stages of evolution alongside computer-generated images of woolly mammoths and giant crocodiles.
Director and executive producer Richard Dale said the aim was to concentrate on a largely unknown chapter of mankind's past.
"This is our own story - the story of all of us - and what better opportunity than to recreate the creatures that came before us over millions of years," he said.
Lord Winston says the series will bring science alive
Fourteen actors taking part in the series underwent a rigorous training programme before filming began.
Voice and movement coaches, together with scientific experts, advised them on how to behave and sound like our prehistoric ancestors.
They spent five hours in make-up each morning and a further two hours at the end of each day to have it removed.
For much of their time on screen they are naked.
In order to make the subject more accessible to the viewer, the episodes focus on particular characters and their relationships with one another.
In one scene, two apes are featured enjoying a romantic dinner for two of termites.
But Lord Winston denied that the BBC was dumbing down by taking a populist approach to science.
He said: "The BBC has done more to improve science education than anyone else.
"We are making it exciting, we are bringing science alive, and I absolutely disagree with the notion of dumbing down."