Mbappe has established himself as one of the best players in the world after bursting onto the scene with Ligue 1 outfit Monaco in 2016-17.
The coveted 21-year-old has already won a World Cup, three Ligue 1 titles and three other domestic trophies for France, PSG, and Monaco, and found himself linked with every major team in Europe's top flight.
Speaking at a commercial event with Nike, Ronaldo shared his views about Mbappe.
“Mbappe is the future and the present,” the former Real Madrid man said.
“He’s a fantastic player, very fast, and he will be the future.”
After scoring 39 goals across all competitions last season, Mbappe has 24 this term – 15 of those coming in Ligue 1.
Ronaldo, meanwhile, is in red-hot form for Serie A champions Juventus in 2019-20. The 35-year-old forward has scored 20 league goals and 24 in all competitions. Ronaldo has netted 12 goals in his past eight matches for Maurizio Sarri's Juve, who are one point clear atop the table.