Dustin Hoffman has revealed why he always tries to say "yes" to signing autographs.

The 88-year-old Hollywood veteran, who has appeared in the likes of Rain Man, The Graduate, Hook, Finding Neverland and more over the years, has credited his longevity in the film world by simply being "nice" to people, and he keeps up that mantra when he's meeting his fans.

Asked about the secret to a long-lasting career, he told Extra: "Life is easier if you're nice to people. It's just easier."

When it comes to autographs, Hoffman admitted seeing the disappointment on someone's face if he turns them down can ruin his whole day.

He added: "If you say no, there's an expression that you see on their face where you have reduced them and that's going to make you unhappy for hours.

"'Why the f***, why did I do that? Why didn't I just sign it?' "

Hoffman, whose new movie Tuner is out this month, also reflected on the way his outlook on life has changed over the years, particularly after writing his memoir.

He explained: "It's interesting because I didn't expect it to be as painful as it is because you're writing about something that's past, and that means it's not gonna happen again, and that's the hard part, I guess.

"That part of my life over and all I have now is this limited amount of time... When you're younger, you don't think of life as being limited.

"It's unlimited, it's just gonna go on. But if you're smart, you realise that every day is a miracle."

Although Hoffman is happy to sign autographs, not every celebrity has the same approach.

The Beatles legend Sir Paul McCartney has adopted a stance against autographs or photos of the years.

When it comes to his signature, he explained to Reader's Digest: "It always struck me as a bit strange - 'Here, can I write your name down on the back of this till receipt please?' Why? We both know who I am."

And he's turned down photos too, insisting that the pictures can't replace a positive exchange.

He added: "What you've usually got is a ropey photo with a poor backdrop and me looking a bit miserable. Let's chat, let's exchange stories."