“I’m a strong believer that if you can get through puberty, you can get through absolutely anything,” says Gok Wan.

With this statement - probably best not examined too closely - Gok Wan announces his new mission. The man who taught women to look good naked is bringing his self-esteem makeovers to the nation’s teens. (Without the nudity, obviously. They are teenagers; that would be weird.)

The result is Gok’s Teens: The Naked Truth, a confectionery-light but ultimately sweet programme in which Gok makes insecure teenagers feel better about themselves. There is, for example, 16-year-old Jake, who is 6ft 9in and 24 stone. “I just want to be normal, like everyone else,” says Jake, who is so terrified of bullies that he will not leave home without his mother.

Then there is Paige, 15, who excoriates herself because she - unlike the internet models she adulates - does not have a gap between her thighs. And 14-year-old Brianna, a recovering anorexic.

Like the Wizard of Oz, Gok has something in his bag for each of them. He introduces Jake to his own brother, a solidly built martial-arts expert, who shows the teenager how useful bulk can be in the ring. Brianna writes down her life story and has it recorded for a body-consciousness website.

And Paige is taken to see a real-life fashion shoot. “Making fashion images is an art form,” says Gok, justifying his former career. “They are not trying to be realistic.” She watches as the model is made up, photographed and airbrushed, and then bursts into tears. “I didn’t know it was like this,” she sobs. “I’m just happy.”

In episode two, he performs the same trick on bullied teens. There is Bethany, a sad-looking 16-year-old in pink glasses, who cannot bear going to school. Then there are Grace and Kate, unequivocally attractive 18-year-old twins, who suffered from being labelled “fat” and “ugly”.

In between, Gok develops a one-off body-confidence lesson plan and presents it to “amaaaaaazing teachers” at various locations. “It’s as important as maths and science and English,” he says, his audience nodding in agreement. But Gok’s teens are transformed because they are offered individually tailored help; a one-hour lesson is unlikely to have the same effect. Ultimately, there is nothing like hindsight to lessen the misery of youth.

Episode 1 of Gok’s Teens: The Naked Truth aired on 7 February and is available on 4oD.