Robin Williams documentary trailer unveils rare footage: 'He was always looking for connection'

The first trailer of the documentary "Robin Williams: Come Inside My Mind" by HBO has stirred the curiosity of many.

It explores the on-screen and off-screen life of the late comedian and iconic actor, Robin Williams. Featuring some of never-seen-before footage of the veteran who committed suicide at the age of 63. The documentary is set to release on HBO on July 16.

The network describes the documentary as "A funny, intimate and heartbreaking portrait of one of the world's most beloved and inventive comedians." Viewers will get a closer look at the iconic actor and comedian through interviews of Hollywood legends and acquaintances and friends of Williams, some of which include the likes of Billy Crystal, Steve Martin, Eric Idle, Whoopi Goldberg and David Letterman. Some other significant details about the actor have also been revealed by his son Zachary.

In the trailer, the late actor's some previously recorded interviews have been featured. At one point, Williams was asked if he suffered from a childhood fear of abandonment, to which he responded, Yeah, it's a primal fear for any child and it dictates a lot of how you deal with life."

Every person is driven by some deep secret. There was fear sometimes to run away from it all, sometimes to run into it all," Williams can be heard saying in the trailer.

Despite his enormous success in career, the Mrs. Doubtfire actor was not able to realise his success. Speaking of this, his son Zachary says, "My father didn't always feel he was succeeding, but he was the most successful person I know."

Williams died by suicide in August 2014 while suffering from a debilitating brain disease called Lewy Body Dementia.

After his death, his wife Susan Williams explained his brain disease in an interview with PEOPLE — it included extreme anxiety, delusions, and impaired movement.

She told the publication, "I know now the doctors, the whole team was doing exactly the right things. It's just that this disease was faster than us and bigger than us. We would have gotten there eventually."

Watch the trailer here.