Bayern announced the France international defender will join the club at the end of the season in a league record deal worth €80 million - almost double the previous incoming record when the Bavarian giants signed compatriot Corentin Tolisso from Lyon a €41.5m deal.
Hernandez will depart his first professional club after establishing himself as a key figure at club and international level with a lucrative five-year contract, but it appears that the Bavarian giants are warming up for a squad overhaul.
Bayer Leverkusen wonderkid Kai Havertz, 19, is widely considered as the future of the German national team and at the tender age of 19, he's already made 97 appearances for the club, scoring 21 goals and providing 22 assists.
"We're in the process of rejuvenating our team, which is the biggest investment program Bayern have ever had," President Uli Hoeness said, explaining the club plan to splash €200m in the next transfer window.
Sport Bild report that the Bavarians are preparing a €75 million euro offer for Havertz but Leverkusen are holding out for €100m - which would effectively break the league transfer record again.
"His contract running until 2022 is very reassuring for us," said Leverkusen sporting director Rudi Voller.
"He's only 19 and has his whole career ahead of him. We want to have some fun with the boy and Kai knows what we can give him."