The 18 year-old midfielder has been a revelation for Bayern Munich this season, establishing himself as the most exciting talent to emerge in German football for several years.
And it's been revealed Real Madrid could've signed the superkid as a junior player.
As German journalist Sebastian Leisgang revealed on the podcast 'Und nun zum Sport', Real Madrid noticed Karl when he was just a child.
After several regional training camps in Germany, the young talent caught the eye of Real Madrid's scouts.
"There he triumphed again and was invited to Madrid and given the opportunity to play at the venerable Bernabéu," Leisgang recalled.
Despite the positive impression Karl made during those trials, his signing never materialised. Far from causing frustration, this decision was celebrated by those closest to him.
“The agreement with Real Madrid fell through. His father told me he was very happy with how it turned out, as he felt it wasn't really about his son, but rather about negotiating contracts with large consulting firms,” explained the German journalist.
In 21 matches this season, Karln has racked up six goals and two assists, all at the age of 18.