Robin Williams didn't feel successful

Robin Williams "didn't always feel" like a success, according to his son.



The late actor suffered from severe depression before his death, and his son Zak, has opened up about the doubts his father had about his own career.



As seen in the first trailer for upcoming HBO documentary 'Robin Williams: Come Inside My Mind', he said: "My father didn't always feel he was succeeding, but he was the most successful person I know."



With director Marina Zenovich at the helm, it looks to give fans' an insight into Williams' life, as he admitted to suffering from a childhood fear of abandonment.



In a previously recorded interview, he said: "Yeah, it's a primal fear for any child and it dictates a lot of how you deal with life."