Lacey Turner (EastEnders, Being Human) will star in the series, which will follow four female flatmates who are secretly witches.
She is joined by Nina Toussaint-White (Doctor Who), Hannah Tointon (The Inbetweeners) and Phoebe Fox (Black Mirror).
Turner will play "immaculately dressed" careerist Stella, while Toussaint-White has been cast as "sexy and stylish" fashionista Jude.
The group's moral compass Grace will be played by Fox, with Tointon starring as the "restless" and "spontaneous" Hannah.
The 'Witches of Camden' must face the challenges of living in contemporary London, as well as their sworn enemies the 'Witches of Kensington', Alexa, India, Romola and Remy.
Switch has been written by Chloe Moss (Prisoners' Wives) and Tim Price (Secret Diary of a Call Girl).
"Switch is a contemporary series about friendship with a spell-binding twist," said ITV's Laura Mackie. "Chloe and Tim have created four fun-loving, free-spirited characters and we're delighted with the direction the series takes."
Produced by Being Human's Philip Trethowan and executive produced by Touchpaper's Rob Pursey, six 60-minute episodes of Switch will go into production in London, Cardiff and Bristol for 11 weeks from April 2012.
