Real Madrid president Florentino Perez has revealed that Paris Saint-Germain will have to pay €1 billon (£727.3m) to sign Cristiano Ronaldo.
The French champions reportedly made a bid for the Portuguese forward during the summer, but Madrid are unwilling to sell the three-time Ballon D'or winner.
Perez revealed that while Ronaldo is not guaranteed to stay with Los Blancos, the club would only accept a fee matching the buyout clause in his contract.
The 68-year-old told reporters: "He has a contract and we want him to stay, but nothing in life is certain. Today, Real Madrid without Cristiano Ronaldo, it is impossible. He is the best player in the world and the most emblematic.
"If PSG want him, it is very easy. If they pay the €1,000m buy-out clause, they will have him."
Ronaldo has scored 313 goals in 302 games since joining Real Madrid back in 2009 but has yet to find the back of the net so far this season.