Kylian Mbappé's known for his feet, but it was the soccer superstar's hands that caught fans' attention on Sunday night ... as he waved 'em in the air like he just didn't care at Bad Bunny's Puerto Rico show!!
The Real Madrid forward hit Benito's concert in San Juan -- and he was spotted on multiple occasions dancing his tail off while the "Titi me preguntó" crooner entertained the masses.
Mbappé was on stage for the gig -- and there was some famous company alongside him, as Paris Saint-Germain star Achraf Hakimi hit up the show as well.