Guenter Euringer in 1973, and today

Guenter Euringer, whose dazzling smile has helped sell millions of boxes of chocolate bars, is now 42 and ready to talk about his secret life as an icon.

His autobiography, The Chocolate Child, was launched in Munich on Tuesday.

The question he is always asked is how much he earned for the advertisement - and the answer, he says, is just 300 Deutschmarks (150 euros or £100).

In 1973 his mother, who worked for an advertising agency, took the 10-year-old Guenter to a photo shoot in Munich, southern Germany, where they lived.

Guenter's hair was long in 1973 - later it was airbrushed out

In the book he says that he felt proud the first time he saw his picture in the supermarket.

But as a teenager he did not want to be identified with the angelic image and avoided talking about the subject.

More than anything, he got fed up with being asked about the money - especially as most people assumed the picture had made him wealthy, or that he received a payment for every box of Kinder chocolate bars sold.

He still lives in Munich with his wife and two children, and works as a cameraman and film-maker.

Curiously, Mr Euringer's face has begun to be replaced on Kinder chocolates in Switzerland in recent weeks.

Mr Euringer himself speculates that he is being phased out because he has dropped his anonymity.

But the food company Ferrero, which owns Kinder, says this not the case.

"In this respect Mr Euringer is misinterpreting things," a company spokeswoman told the BBC News website.