TODAY | August 25, 2013
>>> now to a stunning admission by former heavyweight boxing champion mike tyson . in a news conference he revealed he's been lying about being sober and said he's on the verge of dying. more now from michelle franzen .
>> reporter: it was more self-confession than fight promotion.
>> that's the dangerous thing in this neighborhood alone right here. wants to kill everything. wants to kill me, too.
>> reporter: mike tyson was once the most feared man in the ring, the youngest heavyweight champion winning his first 19 fights by knockout. 12 of them in the first round. but fame and fortune brought trouble and soon his personal life overshadowed his hall of fame career.
>> i haven't drank or took drugs in six days. and for me that's a miracle.
>> reporter: he's on his third marriage and had served three years on a rape conviction.
>> i'm a bad guy sometimes, and i did a lot of bad things. i wanted to be forgiven.
>> reporter: after prison tyson tried to revive his career. but even inside the ring he couldn't escape the bizarre, like when he bit a chunk out of evander holyfield aeroear, or appeared with this frightening tattoo on his face.
>> reporter: but tyson was able to remake himself as an actor. appearing in movies and on tv with the help of spike lee , he even had his own one-man show on broadway.
>> mike tyson , you just never know because he's been so many personas, so many mike tysons over the years you never know what's genuine.
>> reporter: friday we saw the latest incarnation. mike tyson , boxing promoter . the fight he was backing ended in a no-decision, and as for tyson 's future, no decision on that either.
>> i want to live my sober life. i don't want to die. i'm on the verge of dying because i'm a vicious alcoholic. and i've been -- wow. i've been -- god, this is interesting stuff.
>> reporter: for "today," michelle franzen , nbc news.