Tony Robbins might have one of the world's most famous smiles; his beaming confidence has helped sell his best-selling line of self-help books, and fill even his 10,000-seat seminars. What's less known about the iconic motivational speaker is the range and stature of his personal clients. From CEOs to heads of state to Olympic athletes, a wide swath of high-performing professionals (who are already plenty motivated, thank you very much) look to him for help reaching their full potential.

Robbins' expertise in leadership psychology is what brought him to TED, where his spontaneous on-stage interaction with Al Gore created an unforgettable TED moment. It also perfectly demonstrated Robbins' direct -- even confrontational -- approach, which calls on his listeners to look within themselves, and find the inner blocks that prevent them from finding fulfillment and success. Some of his techniques -- firewalking, for example -- are magnets for criticism, but his underlying message is unassailable: We all have the ability to make a positive impact on the world, and it's up to us, as individuals, to overcome our fears and foibles to reach that potential.

Robbins has won many accolades for his work -- including his memorable performance in the Jack Black comedy Shallow Hal. (It was a small but vital role.) His Anthony Robbins Foundation works with the homeless, elderly and inner-city youth, and feeds more than 2 million people annually through its International Basket Brigade.