Lewis Hamilton has confirmed he is an executive producer of an upcoming Hollywood documentary about nutrition and performance expected to be released in September.

The defending five-time driver's world champion, taking part in this weekend's German Grand Prix for Mercedes, said he will appear in the film along with Novak Djokovic, Chris Paul, Arnold Schwarzenegger and Jackie Chan.

"Performance is everything and it all begins with having the right kind of fuel in our bodies," Hamilton said on Twitter.

"I'm proud to be Exec Producer on 'The Game Changers'. It's a revolutionary new documentary movie and I can't wait for you guys to see it this September."

The film, in which Titanic director James Cameron is also involved, focuses on veganism, nutrition and fitness and raises questions about the value of meat in a diet. It is directed by Louis Psihoyos, who won an Oscar for the documentary feature The Cove in 2010.

Hamilton, who became a vegan two years ago, spoke of the importance of diet for performance.

"Just look at Djokovic: that little bit extra that's there, that people are reluctant to look in to ..." he said.

Hamilton will be involved in the making of another film this weekend as the crew from a Netflix documentary, Drive to Survive, go behind the scenes with his Mercedes team.

"I don't have to do much, just do my job and hopefully they'll catch the good sides of me and edit out the bad," he quipped.