A Nintendo insider has revealed that Nintendo designer Shigeru Miyamoto has been ordered by the company to not discuss his hobbies in public, after fears of other companies using them for game ideas.

Miyamoto has adapted some of his favourite hobbies into highly profitable games for Nintendo, and the company worries that even a slight glimpse into his head could be worth "billions".

Firstly, Miyamoto made Brain Training - the smash hit for Nintendo DS - after developing an interest in puzzles. Next, he took up more exercise, and thought up the idea for Wii Fit. Now, after taking up music lessons, the highly-anticipated Wii Music was born - all set for an October release in Japan.

Now, according to sources at Nintendo, the games designer has been banned by the company from speaking publicly about his any of his interests.

After luring in gamers with characters such as Zelda and Mario years ago, it is now Miyamoto's vision that has taken Nintendo into the next-gen console era. With the success of the Wii continuing to impress it seems even the most fleeting insight into how Miyamoto spends any of his time is creating a bit of a buzz among fellow developers.

So which of Miyamoto's current past times will be the next big thing in a few years in the virtual world? We'll just have to wait and see.