The 53-year-old actor starred as Chandler Bing on the sitcom alongside Jennifer Aniston,
He said: "How can you not have a crush on Jenny, Courteney (Cox), and
The '17 Again' actor - who also starred alongside Matt LeBlanc and David Schwimmer on the classic sitcom and saw his character go on to marry Courteney's alter ego Monica Gellar - struggled with addiction to drugs and alcohol during the height of his fame and explained that while he "never" took booze to work with him, he would often show up on set "blindly hungover."
In a clip from his upcoming interview with Diane Sawyer on ABC News, he said: "Early on yes, and I made a rule that I would never drink or take anything at work. I would never do that, but I would show up blindly hungover. Like shaking."
"I loved Chandler, I loved the show. And I knew 'remember this because it's going to be the best time of your life.' And I knew I would never forgive myself if I messed this up."
He said: "I think they'll be surprised at how bad it got at certain times and how close to dying I came. I say in the book that if I did die, it would shock people, but it wouldn't surprise anybody. And that's a very scary thing to be living with. So my hope is that people will relate to it, and know that this disease attacks everybody. It doesn't matter if you're successful or not successful, the disease doesn't care."
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