Mike Tyson has claimed he and Robin Williams used to use the same ''low-life dealer''.

The retired boxer has opened up about battling depression and mental illness and admitted he used to chat with the late Hollywood actor - who committed suicide aged 63 in August - about depression and attend the same meetings as him.

Speaking on 'The Howard Stern Show' on SiriusXM Radio, he said: ''I knew Robin. We'd meet each other. People that deal with this situation, we know each other. We all know each other. We meet each other. I've been at a meeting with him, yes.

''This is very interesting. When I met him he said, 'I was waiting for you.' And he started telling me about somebody I was purchasing something from ... You look up to Robin so in my mind I'm saying to myself, 'How does he know this low-life dealer that I know?' ''

While the 48-year-old sportsman admitted he was devastated when Robin - who battled depression - died, he was also distraught when Philip Seymour Hoffman died of acute mixed drug toxication in February because he felt the 46-year-old actor's death was closer to home.

He added: ''When Mr. Hoffman passed away, this is what you say, 'He was sober for twentysomething years and he died. What kind of chance do I stand?'

''If you have a mental illness you're going to think about suicide. Suicide is our comfort. You always think about it.''

Tyson has previously been very open about his battle with depression, and admitted on the radio show that he is ''mentally ill'' and goes into ''depressed modes'' at times.

Speaking to Howard, he explained: ''I have a mental illness, forget depression. I'm mentally ill.''

He then joked: ''Of course I am, I'm talking to you.''

When asked by the presenter if he really considers himself mental and suffers from a mental illness, he replied: ''I would say I do. If is I was to be really honest. When you look at me now, sometimes I've run into my depressed modes too.''

When asked if he was on medication, he said: ''No ... you can't have a vain guy on medication.''