Al Pacino stars in two movies shown at the 71st Venice Film Festival, which meant he had to do a double round of media events, but the 74-year-old said he drew energy from the crowds that turned out to see him.
"People charge you. They make you feel as though 'Oh! I've done things. I've done a few things'. You really forget, you do, mercifully you do," he told Reuters in an interview on Sunday.
"Imagine going to a place like that and just drooping along? What would that do? Everybody would go 'poor guy, poor me, poor them'. So you go with the glow, as they say."
Pacino was in Venice to boost director Barry Levinson's "The Humbling", based on a Philip Roth novel about an aging actor who feels like he is losing his acting ability, but who is reinvigorated by a late-life affair with a young woman.
His other film, "Manglehorn", directed by David Gordon Green and which is in competition for the Golden Lion prize, is about a Texas locksmith who has never gotten over a love affair that went sour, and has walled himself away from other people.
Pacino said some of his professional peers had misgivings about him playing an actor losing confidence.
"I mean, fellow actors have said, 'I don't know, Al, what you're doing here doing this?' I said, 'I don't know why'," he said.
"I see it in the distance and it's not me, it's just not me. I can try to understand what he's going through but it isn't (me). I have a knowledge of it, I have a knowledge of the world this guy comes from and the drudgery of it and the pain of it but it's not me."
He said the portrayal was not based on anyone he knew, but added that he and other actors sometimes base characters they play on people they know.
"It's great when you get an idea like that," he said. "When (Laurence) Olivier in London got the idea of (Shakespeare's) 'Richard the Third' by doing a portion of this guy he knew and it turned out to be spectacular, so there's that too.
"You long for that. That's a lucky break. You want your director sometimes to say 'Why don't you do that but do it the way George Raft (an American character actor who specialized in gangsters) would do it?'
"And you suddenly get an image and it's wonderful when you can get that."
"The Humbling" was showing out of competition in Venice.
(Writing by Michael Roddy; Editing by Stephen Powell)