Sharing his thoughts on the advertising world, Leto said that "when advertising is creative, it's not advertising; it's transcendent, it's art".
Advertising can't save the internet, the world and certainly not your brand. First of all, you have to make something great.
However Leto - who posed for a selfie with a fan during his talk - also said that parts of the industry were guilty of bad work, adding that advertising could "not save the world".
"Advertising can't save the internet, the world and certainly not your brand. First of all, you have to make something great. You can't resuscitate a stinking pile of yak turd - and god knows you've tried," he told the appreciative audience to sounds of whoops and cheers across the auditorium.
Leto said that it was the role of advertising to explain how brands can make people's lives better.
"When brands speak, reaching out to try to communicate, the most important thing is authenticity. Telling the truth. Otherwise just leave me the fuck alone.
"If you can't do that, at the very least make the advertising beautiful or titillating."
Learning from failure
Speaking about his personal success, Leto said failure was important, but bravery was also required.
"You have to fail. Sometimes you succeed more from failure than from success. You fail, fail, fail and learn."
He added: "As an artist I can say 'fuck you' and do whatever I want. But I believe everyone should take that approach. I have 24 people who work with me and I value that. [For] people who take risks, there's a lot of reward."