Sir Martin Sorrell told us why he just created a new agency with Snapchat

Snapchat has partnered with the world's largest advertising agency holding group WPP, and The Daily Mail to form a content marketing agency, the companies announced at a press conference at the Cannes Lions International Festival of Creativity on Tuesday.

"Truffle Pig" will use Snapchat, the Daily Mail and Elite Daily to test social content and marketing. The agency, which can work with WPP clients and other brands, will offer services such as positioning and messaging, content projects, video and photography, social media management, audience development, and insights and analytics.

It will be led by WPP's Alexander Jutkowitz, managing partner of Group SJR. All three companies are equity owners.

We spoke to WPP CEO Sir Martin Sorrell at the Cannes Lions Festival of Creativity ahead of the announcement about what first appealed to him about Snapchat and how the deal came about.

Sorrell told us he first met Spiegel in Chicago about six months ago, after an introduction from the The Daily Mail's US CEO Jon Steinberg.

Sorrell and Spiegel had lunch at Soho House. Spiegel was keen to sign up some of WPP's clients to sponsor the then-new Discover content section on the app, of which The Daily Mail is a content provider (alongside other brands such as Vice - in which WPP owns a stake - Cosmopolitan, and National Geographic.)

Sorrell admitted that he initially "insulted" Spiegel by accident: "I said 'you're the only billionaire I know at the age of 25.' And he said: 'I'm 24.'

Sorrell told us: "He was keen to get people to sponsor [Discover] at $750,000 a pop. Most of our clients said 'where's the data?'- so it was quite difficult to do that. I think his approach is very interesting, and we'll see."

The main interest in forming a partnership with Snapchat is primarily around "developing social content," and Sorrell said WPP will help answer its clients' questions around data "to try to build a more substantiated model."

The appeal of Snapchat to WPP was around its unique, engaged userbase of younger people.

Sorrell said: "If you look at the data that our own futures group has produced, on the media habit of centennials - [people aged 0-18] - their attitude to Snapchat is markedly different from Facebook, so that seems to indicate generational changes ... Facebook is the largest country on the planet [in terms of users] but maybe centennials don't want that. They want 'Mission Impossible' [style] destruction. They want to keep stuff away from the prying eyes of others, family, and whatever else. But whatever the reason is, it's different. Therefore it's volatile. It indicates there's volatility, and it pays to be involved."

The Daily Mail's Steinberg recently compared Spiegel to a young Martin Sorrell. We asked Sorrell whether he sees any of himself in Spiegel. He responded: "No, no - I wish I did!"