Lubricants company Castrol will pay Manchester United and Portugal star Cristiano Ronaldo some US$13.5 million to have the player endorse its brand in the build up to the 2010 Fifa World Cup.

Ronaldo, Fifa World Player of the Year in 2008 and one of world soccer's most commercially valuable men, will become a brand ambassador for Castrol until 2011.

The Portuguese, who many believe has yet to fulfil his enormous commercial potential, will be the face of the lubricant as the company seeks to capitalise on its association as a sponsor of the World Cup in South Africa next year.

Ronaldo will lead new Castrol Edge and Castrol Power 1 brand communication campaigns as well as supporting the exclusive workshop range of Castrol Professional products.

Castrol is part of the BP group of companies and has a strong history in sports sponsorship. Naturally, the company has had a longstanding and heavy involvement in motorsport but has recently become more involved in soccer. It sponsored the shirts of Swindon Town FC between 1995 and 1996 and, more recently, the Uefa Euro 2008 tournament.