Perez - who is reportedly dealing with an unhappy Cristiano Ronaldo amid tax claims in Spain - was asked about Madrid's interest in Mbappe and he admitted the LaLiga champions are following the 18-year-old.
The same article states that Mourinho is of the opinion that Ronaldo is in decline, despite the Real Madrid star scoring twice in a 4-1 win against Serie A giants Juventus in the Champions League final.
The Portuguese manager owes Spanish tax authorities 3.3 million euros (about 2.91 million pounds or N1.46 billion), a Madrid prosecutor said in a statement. The 29-year-old has helped the European heavyweights lift 29 titles during his 13-year senior playing career, and has also been crowned the victor of the prestigious Ballon d'Or award a record five times.
"I still haven't spoken to Cristiano Ronaldo".
The playmaker is considered the best player of all time by many and has a strong sporting rivalry with Real Madrid man Cristiano Ronaldo.
The Spain worldwide nearly joined Madrid in 2015 until the blockbuster transfer collapsed and he continues to be linked with a switch to the Santiago Bernabeu, but Perez insisted the capital club are happy with Navas. "We've not received offers for him (Ronaldo), Morata or James".
Perez's latest four-year term has started as many of his previous ones have - with frenzied transfer speculation about which big-name players might arrive at the club and, perhaps more crucially in this instance as Ronaldo's future dominates the headlines, who might end up leaving.
In quotes carried on Marca's website, Perez said: "I have not spoken to him".
Costa Rica goalkeeper Navas was criticised at several points last season for unconvincing displays which cost Real points leading to reports in the Spanish media that the club would make another move for De Gea.
Real Madrid has also declared its support for the 32 year old.
Manchester United have so far made no comment on reports they are interested in buying back the player for an estimated €200 million, on top of the release fee.