The children's programme was devised by Russell T Davies and Phil Ford who discussed creating a show involving the supernatural meeting sci-fi.
Wizards Vs Aliens is sees a 16 year-old boy Tom (Scott Haran) and his friend Benny (Percelle Ascott) battling a race of aliens the Nekross who have travelled to Earth to feed on magic.
Describing the 12-part series, Davies says: "Wizards Vs Aliens is a fun adventure story about a young boy called Tom and his best friend Benny. Tom’s secret is that he’s a wizard, and you think that would be exciting enough, but then they discover aliens exist and are coming to Earth to consume all the magic. Let battle be drawn!"
The cast includes Brian Blessed, Annette Badland, Michael Higgs, Gwendoline Christie, Jefferson Hall and Brian Miller.
The opening two-part story - Dawn of the Nekross - is written by Phil Ford and will be broadcast across today and tomorrow on CBBC at 5.15pm.
In episode one, Dawn Of The Nekross (part one) Tom Clarke is hiding a secret – he’s a schoolboy wizard! But when the magic-eating alien Nekross arrive on Earth, a battle for survival begins. Tom must use his magical powers to protect his family – but only the school geek, Benny, can help him against the plans of the terrifying Nekross King.In part two of Dawn Of The Nekross, with his Gran trapped in outer space, Tom and Benny must dare to go inside the mystical Chamber to ask the mysterious Randal Moon for help. But with time running out for Ursula, and Tom’s dad joining the fight, can even a magical hobgoblin fight an enemy from beyond the Earth?