Speculation over Paris Saint-Germain star Mbappe continues to make headlines as Zinedine Zidane's Madrid reportedly eye the France international.
Zidane has made no secret of his admiration for Mbappe, who dismissed talk over PSG contract negotiations earlier this month, while the 21-year-old revealed the Madrid boss was his idol growing up.
Nacho was asked about Mbappe following Madrid's 3-1 Copa del Rey win over Unionistas de Salamanca on Wednesday.
"If he's sending us signs, we have to be alert to receiving them," Nacho told reporters.
After scoring 33 Ligue 1 goals last season, Mbappe has 13 for defending champions PSG this term.
Mbappe has 21 goals across all competitions for Thomas Tuchel's PSG, who are preparing for the Champions League last 16 against Borussia Dortmund.