Hollywood star Matthew McConaughey says he started keeping a journal at the young age of 14. The Academy Award-winning actor, who has penned an autobiography titled "Greenlights", says he does not write things so he can remember, he writes things down so that he can forget them.

McConaughey opened up on the subject while speaking to actress Drew Barrymore on her popular chat show. He was a guest on "The Drew Barrymore Show" post the recent success of "Greenlights".

Barrymore said: "I love the poetry of the way you speak and think and I have been having the most incredible time reading your book. I love that in the opening you mention that this is not an advice book and that you aren't preaching but rather says that this is a playbook based on adventures of my life which is such a nice way of getting insights into your life journey."

McConaughey called his autobiography "an approach book" and "not an advice book", because nobody likes to be told what to do, especially the actor.

He added: "But I did have a great time sharing certain things of my own life, certain things in life that have given me satisfaction, approaches that I have taken at that I have failed at. What has helped me are my journals of my successes and failures that I have kept with me for the past 36 years."

McConaughey also opened about his love for journaling during his chat with Barrymore.

"I started keeping a journal when I was 14. A lot of men and women do so at that age. I was confused and I wrote down every question that popped in my head and every little problem I had. Later on, I continued to write when things were going well, when I was doing well, when my relationships with people improved," he recalled.

The actor added: "But when I look back, I think to myself the kind of flow I was in at that time. What journaling does for me is that I don't write things so I can remember, I write things down so I can forget them. If I want to go back to the inspiration I had, I know that it's been written down and I don't have to think hard about remembering it."

"You and I both have an optimism problem," Barrymore replied, on the show that airs in India on Zee Cafe.