LONDON (AFP) - Cristiano Ronaldo will finish his career at Real Madrid, the Portuguese superstar's agent said on Tuesday before revealing that the buy-out clause for the world footballer of the year is one billion pounds (S$2.03 billion).

"He is the best player ever in the world. You can't compare him with anybody else," agent Jorge Mendes said of Ronaldo in an interview with the BBC.

When asked how much is Ronaldo worth, Mr Mendes said: "Cristano Ronaldo? One billion pounds. His buyout clause one billion, so it is one billion. It is impossible to find someone like him.

"If for any reason the club decides to sell him tomorrow for 300 million pounds, someone will pay," Mendes added.

But the agent said there was no danger of his 29-year-old compatriot, voted the world's best player for a third time last month - beating Barcelona's Lionel Messi to the award - leaving Real's Bernabeu Stadium.

Asked if Ronaldo, who joined Real from Manchester United for a world record 80 million pounds in 2009, would end his career with the Spanish giants, Mendes said "for sure".

"He will not leave Real Madrid," Mr Mendes insisted.

Unless someone pays one billion pounds, of course.