"It represents a historic agreement that positions our organization as 'More than a club' throughout the world," Barcelona president Joan Laporta told the club's official website.

"We are very satisfied because it is the beginning of a challenge and this challenge is beginning to turn into concrete objectives."

The club have never placed any sponsor on their jersey since being established in 1899.

Barcelona, though, put an ad for Catalan station TV3 on the left sleeve starting from 2005.

Laporta, who was recently elected for a second stint in charge of the Catalans, said the deal highlights Barcelona's social role and their plan to help children worldwide.

"It is an initiative with soul, it means winning the 'Champions League' on a social level. Our organization is positioning itself to help children," Laporta said.

"That means that Barca has a future as it is helping the children of the world. It's a historic moment as it is a prestigious logo and not just a publicity brand.

"It's an honor to wear the UNICEF logo because it's an agreement without precedent for UNICEF as well."