Williams, who took his own life in 2014, was close friends with the Superman actor, who passed away nine years after a horse-riding accident left him paralysed in 1995.

In a new documentary, titled Super/Man: The Christopher Reeve Story, many areas of Reeve's life are explored, including his friendship with the comedian and actor.

Speaking in the film, Fatal Attraction star Close says: "I always felt that if Chris was still around, Robin would still be alive."

Williams and Reeve had been close for decades after rooming together at The Juilliard School in New York in 1973.

At the time of his death, Williams was suffering from Lewy body dementia, an incurable brain disease which had been misdiagnosed as Parkinson's disease.

Many of the Good Will Hunting star's friends and colleagues recalled that Williams' deteriorating health led to an intense depression that left him "sobbing" and believing he no longer knew "how to be funny".

This is not the first time Close has said she thought Williams would still be alive if Reeve was too.

ET News reported in 2017 that, while speaking at the Christopher & Dana Reeve Foundation's annual charity gala, Close described Williams and Reeves's "connection" as "the stuff of legend".

"It not only endured, but became a life-giving force sustaining them both," she said.

Recalling how, during her time filming The World According to Garp with Williams in 1982, Reeves "would literally swoop in, piloting his own plane, scoop Robin up, and away they would fly for the weekend".

"On Sunday, late afternoon, Chris would swoop back in and deliver Robin back - I have to say a little worse for wear."

She said the pair were "on top of the world" when they spent time together, adding: "They were living the kind of fast and crazy life that our business can hand to you if you become a wildly famous phenomenon, practically overnight."

"I am convinced that if Chris were still with us, Robin would be too."

Anyone feeling emotionally distressed or suicidal can call Samaritans for help on 116 123 or email This email address is being protected from spambots. You need JavaScript enabled to view it. in the UK.

In the US, call the Samaritans branch in your area or 1 (800) 273-TALK.