Household products giant Unilever has signed a "groundbreaking" advertising and research contract with magazine-to-website giant AOL Time Warner.

The "multi-million dollar" deal will see Unilever products, such as Dove soap and Pond's cream, advertised across the range of AOL Time Warner media, including the Turner TV network, Time magazine and the America Online web services.

The announcement comes amid a growing trend among advertisers to seal cross-media agreements, with Procter & Gamble last May signing a $300m internet-to-billboard contract with media giant Viacom.

But the deal between AOL and Unilever, the world's largest advertiser, will build on traditional ad arrangements by including clauses on sharing internet know-how, and knowledge on customer feedback and marketing, the firms said.

"This is a groundbreaking agreement that goes beyond simply agreeing to a traditional multi-platform media deal," Charles Strauss, president and chief executive at Unilever US said.

"Our two companies will work together, both in the US and in Europe, on customizing brand growth and marketing strategies to drive our leading brands."

AOL chief Bob Pittman said the deal would see Unilever develop relationships with customers "in new and innovative ways".

The web co-working clause will see AOL, which in America Online has the world's biggest internet service provider, swap research with Unilever's New Jersey laboratories, which are developing next generation mobile and in-home technology.

Unilever shares closed up 3.5p at 553p in London on Wednesday.