Karl Lagerfeld stars in a new documentary about his role as a ''fashion missionary''.

The Chanel mastermind is the focus of a four-hour German biopic about his life and career, 'Mode Als Religion' (Fashion as a Religion), which presents the eccentric designer as a figure to be revered, likens fashion magazine to the Bible and compares models to angels.

Martina Neuen, the Cologne-based television journalist behind the film, told WWD: ''It's a bit tongue-in-cheek. It cannot offer you redemption or anything eternal.''

The project strives to prove that fashion and religion are similar, using powerful symbols and a system of beliefs to bind people together, and Martina even oversees a scientific experiment to compare the brains of a Catholic priest and a devoted fashionista.

She insisted: ''The emotional reactions are the same.''

Karl allowed the journalist unlimited access to his fashion shows and photography over 16 months, and shared secrets about his life and career path on camera.

The documentary also features interviews with influential fashion names including Diane Kruger, Sarah Jessica Parker, Claudia Schiffer and Linda Evangelista.

Martina added: ''He's the most impressive person I've ever met. He's a true individual, and there's a lightness of being around him.''

The documentary will air on September 7 on Vox in Germany.