Will Smith says he "has not been drinking for more than ten years" as he prepares to run his first half marathon

He is one of the biggest movie stars on the planet.

But before becoming a household name, Will Smith "has not been drinking for more than ten years" for the purpose of discipline.

The 50-year-old actor made the revelation during an episode of his Facebook Watch show that follows him as he checks things out of his to-do list.

In the episode, the Bad Boys star travels to Cuba to run his first half marathon, with three weeks' notice.

It is a sporting feat that he has never tried before, and he is reasonably worried: "I think of all the lists of categories, it is the one that concerns me the most," he explained.

"For example, in my honesty with myself, I'm really not sure I can run 13 miles."

Smith spent the three weeks leading up to the event preparing for a demanding training and being examined by a doctor.

During a physical stress test, he undergoes an electrocardiogram (ECG), relays some of his current discomfort and also discusses his former head condition.

"Being out of shape is a bit new to me," he says with his short circuit to the camera.

He continued, "I have not been drinking for more than ten years."

"You know, during my ascent as a movie star, I was very disciplined, so being in this place of my life, even something as simple as removing my shirt when i am in bad shape, you know this for me now allowing me to be seen in a less than optimal way is new.

He went to explain that, young man, "he was ready to die to become the biggest movie star of the world".

But at this stage of his life, he found a point of view, "With age, I no longer feel the pressure to follow the brand image displayed as I did before, and to live with these imperfections and to accept my weaknesses have brought me so much freedom.

"I am the happiest of my life."

Will completed the marathon.