After finding himself dropping down the pecking order at Stamford Bridge, the Chelsea academy product agreed to move to Italy with AC Milan on a loan deal until the end of the season.
The Rossoneri have an option to make the move permanent in the summer with a payment of €28m to Chelsea.
Tomori has wasted little time in establishing himself in the AC Milan team and he has garnered widespread praise for his performances.
Kjaer is particularly impressed with the mentality he has shown, which displays his willingness to prove himself.
The Dane also feels Tomori’s pace and aggressive style makes him a rare kind of centre-back in Italy.
Kjaer said in a press conference: “I didn’t know much about Tomori, but the mentality with which he entered showed a hunger to prove himself.
“He is a fast and aggressive defender, which is rarely seen in Italy and that is important for central defenders.
“He is a young player with many qualities.”
It remains to be seen whether AC Milan are prepared to pay the money needed to secure Tomori on a permanent deal at the end of the season.