Story highlights "I wasn't that serious" - regrets Usain Bolt

Jamaican superstar won nine Olympic sprint golds

New film - I Am Bolt - released worldwide Monday

(CNN) A new Usain Bolt biopic -- I Am Bolt -- aims to inspire future generations, but it also gave the Olympic great a lesson too.

The 30-year-old, who showed a natural talent for sprinting growing up in Jamaica, has won nine Olympic gold medals but could his haul have been even greater?

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"When I started out I wasn't that serious," he told CNN in London, where he will end his sprinting career at the 2017 world championships.

"I was more relaxed and chilled and just living my life. I would say [to my younger self] 'get serious' so my career could start earlier," added Bolt as he talked about the film, which released worldwide Monday

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