Leonardo DiCaprio saved a man who fell overboard in the Caribbean in a "billion to one rescue" after using his luxury boat to search for the missing person.

The Oscar-winning actor was holidaying near the island of St Bart's when an emergency call went out seeking help to locate the man, The Sun reported.

According to the newspaper, the inebriated 24-year-old French crewman had fallen from a Club Med yacht near St Martin on December 30.

The man had been treading water for 11 hours when he was rescued by DiCaprio's vessel near Saba island, around 28 miles from St Martin.

“Leonardo played a blinding role in his own real-life Hollywood movie," a source told The Sun. "[DiCaprio's crew] were the only responders, and his only chance of survival, despite being hours away.