Buffon, 40, is set to end his playing career at the end of the season, unless Juventus win the Champions League, in which case he will seek to play in the Club World Cup.
With Los Blancos having taken a 3-0 lead in the tie at the Juventus Arena, however, the Bianconeri will need an extraordinary turnaround to overturn the deficit at the Bernabeu.
“I don’t know if this will be my last, and I don’t want to talk about it now,” Buffon told Mediaset.
“But any professional footballer would aim to make their last Champions League appearance at the Bernabeu against Real Madrid.
“As a kid, I would have signed for my last game in the Champions League to be here.”